A few days ago I blogged my dissatisfaction with the coverage of the NLST trial by "The Health Show" on NPR. On the show, the host interviewed Dr. Regina Vidaver, the head of the National Lung Cancer Partnership, and the interview proceeded along predictably sensationalized lines of popular health reporting. For my substantive criticisms you can refer to my previous post. What has followed my posting of the piece is what is unusual, and perhaps tends to get lost in the heat of criticism. Dr. Vidaver promptly contacted me to schedule a time to talk. I just got off the phone with her and felt compelled to write a follow-up (with her consent, of course).
The conversation centered around some of my major criticisms of the interview: not emphasizing enough smoking cessation as the main intervention needed to reduce lung cancer mortality, the issue of false positive CT findings followed by the ensuing potentially invasive work-up with its on occasion adverse consequences, the costs in the setting of finite resources. Dr. Vidaver pointed out, and this did not surprise me, that her strong initial statement on the need to fund smoking cessation did not make it into the final segment. Neither did any discussion of the potential for false positive findings and their consequences. She also articulated to me that, although she and her organization believe that smoking prevention and cessation remain the single most effective public health approach to curtailing lung cancer mortality, they also believe that reliable screening tools are necessary, particularly since never smoking or quitting smoking does not guarantee that one will not die of lung cancer. In fact, she hopes for the development of an intermediate marker to help risk stratify those population members, be it smokers or non-smokers, who are at a heightened risk for lung cancer and who might then be candidates for close and regular radiographic screening. As for the issues of cost, she indicated that her organization does not get involved in this sticky policy issue.
So, this interaction has raised a couple of interesting points for me. First, how much control does the guest, or one being interviewed in general, have over the final content of the interview? I worried about this myself when in 2008 one of my papers on Clostridium difficile epidemiology in the US hospitals garnered some press attention. Out of the blue, I was contacted by Mike Stobbe from the Associated Press, who was interested in asking me some questions. Being largely inexperienced in talking to the press, and unaware of Mike's sophistication and integrity, I was nervous. This made me quite cautious about how I represented our data, as well as other relevant science. For about 48 hours after the paper went live, I received a constant stream of calls and e-mails requesting newspaper and radio interviews. I was even interviewed by Jon LaPook, the CBS health reporter. Throughout that experience I was exceedingly circumspect, and may have missed an opportunity to drive home some messages firmly. This, my friends tell me, is the difference between science and advocacy. So, while I am currently creating the nexus between the two, at that time I clearly chose to keep them separate.
But what about journalism and advocacy? Were the show's host and producers unwittingly engaging in advocacy to get people to accept the screening paradigm to the exclusion of other, possibly more sensible, interventions? Or was it just that there is nothing new and shiny about the smoking cessation message, and they just did not want their listeners to turn the dial? I do not know the answers to these questions, as they have not volunteered their comments. But you can bet that I will be that much more vigilant of their reporting in the future.
The second point raised for me by my interaction with Dr. Vidaver is the issue of costs. I completely understand why a disease advocacy organization would want to steer clear of addressing this third rail of healthcare policy. The impression among most of my fellow Americans is that bringing costs into the equation diminishes the value of one's life. Yet, our lives are constantly being priced, and rather more crudely and expediently than health economics dictates. Paradoxically, no one seems to mind the fact that our politicians and pundits price our lives every day by prioritizing economic interests (such as the entire sector of the economy powered by tobacco) above human lives. How many lives lost to this addiction pay for the jobs and the salaries of Philip Morris executives? Why is this not seen for what it is: a trade-off between a citizen's life and profit for a producer of poison? How is asking the difficult cost of care questions, where the trade-off is often between prolonging suffering at the close of life and redeploying these resources toward preventing disease, so much more deplorable than paying tobacco companies to kill us?
These are odd contradictions, if you ask me, and all emblematic of our predictably irrational human nature. At the same time, these issues will not go away, and just because they are difficult does not mean we should bury our heads in the sand to avoid them. Nothing replaces a cogent national discussion to get at the much needed solutions. Yet, isn't it time we just said no to tobacco? Would this not eliminate the huge policy headaches of how to finance screening for lung cancer and deal with the avalanche of false positive results and ensuing complications among perhaps as many as 10% of the US population? Does it not make more sense to eliminate 85% of all lung cancer deaths by getting rid of the poison than to eliminate 0.3% of all lung cancer deaths while adding untold hundreds of billions of dollars to our already mammoth healthcare bill, not to mention causing further escalation of healthcare-associated injury and death by chasing false positives?
Monday, November 29, 2010
Sunday, November 28, 2010
Top 5 this week
Wednesday, November 24, 2010
Our nation's shocking Lady Macbeth moment
I am just cynical enough not to be easily shocked. This cynicism extends to our societal woes, and particularly our social and economic inequities driven by the worship of the free market theories. Yet, I truly was shocked by this article in Scientific American. And no, it was not the scientific confirmation of our intuition that poverty breeds stress, which in turn breeds difficult behaviors. What got me was this paragraph:
But why let facts get in the way of our reality? Let me say it again: "inequality is killing our kids"! And it is doing it by relegating mothers to abuses of abject poverty, to be perpetuated by these holy "free" market forces (which incidentally are not free at all, but are sold to the highest bidder by the government, with each of us standing by eager to defend our own piece of the pie at all costs). This is not just deplorable, it is criminal. These maternal infanticide statistics, along with other less visible abuses concentrated in the socially expendable poor masses are on all our consciences. We may try to evade the crushing weight of this responsibility by robotically parroting free market mantra and personal responsibility lies. This will not change the fact of the blood on our hands.
The level of our healthcare debate is but a symptom of our willingness to walk away from this maternal holocaust. And no, this is not a socialist view, it is not a conspiratorialist view, and it is not anti-freedom view to acknowledge the moral bankruptcy of sweeping this problem, invisible to most of us privileged Americans, under the rug.
The realization is viscerally painful, yet the time has come. For those of us who need scientific evidence before we make any move to change our behaviors, there it is, for the taking. Science has spoken: "inequality is literally killing our kids". This is a call to social action. This is a call to save our future!
The United States currently leads the developed world with the highest maternal infanticide rate (an average of 8 deaths for every 100,000 live births, more than twice the rate of Canada). In a systematic analysis of maternal infanticide in the U.S., DeAnn Gauthier and colleagues at the University of Louisiana at Lafayette concluded that this dubious honor falls on us because “extreme poverty amid extreme wealth is conducive to stress-related violence.” Consequently, the highest levels of maternal infanticide were found, not in the poorest states, but in those with the greatest disparity between wealth and poverty (such as Colorado, Oklahoma, and New York with rates 3 to 5 times the national average). According to these researchers, inequality is literally killing our kids. [emphasis mine]So, here we are, in the 21st century dystopia of escalating social inequities that are "literally killing our kids"! Yet, people who should know better, knowingly or unknowingly, continue to advocate the failed philosophy of objectivism, a system that advocates pursuit of rational self-interest, the supremacy of individual rights (selectively applied to the haves), and the cheer-leads for keeping government out of private market interactions (yeah, that worked really well with the banking industry).
But why let facts get in the way of our reality? Let me say it again: "inequality is killing our kids"! And it is doing it by relegating mothers to abuses of abject poverty, to be perpetuated by these holy "free" market forces (which incidentally are not free at all, but are sold to the highest bidder by the government, with each of us standing by eager to defend our own piece of the pie at all costs). This is not just deplorable, it is criminal. These maternal infanticide statistics, along with other less visible abuses concentrated in the socially expendable poor masses are on all our consciences. We may try to evade the crushing weight of this responsibility by robotically parroting free market mantra and personal responsibility lies. This will not change the fact of the blood on our hands.
The level of our healthcare debate is but a symptom of our willingness to walk away from this maternal holocaust. And no, this is not a socialist view, it is not a conspiratorialist view, and it is not anti-freedom view to acknowledge the moral bankruptcy of sweeping this problem, invisible to most of us privileged Americans, under the rug.
The realization is viscerally painful, yet the time has come. For those of us who need scientific evidence before we make any move to change our behaviors, there it is, for the taking. Science has spoken: "inequality is literally killing our kids". This is a call to social action. This is a call to save our future!
Tuesday, November 23, 2010
Quality improvements: Rewarding the signal and not the noise
In my post yesterday I questioned whether our current incentives are truly promoting quality or just prettier looking documentation. I used Dan Ariely's discussion on the fallacy of rewarding outcomes in the world of business as a jumping off point. But today it occurs to me that some of his suggestions about changing course to start moving in the direction of best achievable quality need to be further adapted to healthcare environment. So, I will try to do it here, and would love feedback, if you have any.
Here are Dan Ariely' recommendations on how to start rewarding the signal instead of noise:
1. Change the mind-set -- This applies to public reporting of never events. Tracking these on a large scale, say, city, state, country, is necessary so that we know how we are doing at not inflicting harm. However, at the level of an individual institution, there is so much variability in events such as infections, mortality, etc., that using them as a public humiliation tool is not sensible.
2. Document crucial assumptions -- We can adapt this to a healthcare setting to reflect how we build our systems to maximize prevention efforts. That is, in the setting of perpetually imperfect and oftentimes substandard evidence, in addition to tremendous inter- and intra-patient variability, a sensible evaluation of how best to approach each patient in the context of preventing complications is needed. If the evidence for interventions is valid, but the circumstances of how we understand the patient's condition change, we should not either reward or punish the provider or the institution for the associated outcome.
3. Create a standard for good decision making -- This is pretty easily adapted to our setting. Transparency, being up to date on the evidence, as well as the information on the particular patient, considering all that is reasonably available, and without conflicts of interest, are all part of the mandate for intentional quality improvement and individualized care. This also sets the criteria for what good decision support should look like.
4. Reward good decisions at the time they are made -- No translation necessary here, I think. The only thing I want to say is that there are ways other than financial to reward good performance, and we need to understand how they can be used to promote desirable behaviors among clinicians.
So, public lashings for having blood stream infections, ventilator-associated pneumonia and similar complications are not sensible. Relying on them simply reinforces the God complex in medicine and punishes the wrong link in the chain of events.
In general, it is time to let what we are learning in behavioral and cognitive sciences about what makes us tick help effect good behaviors at the bedside (and in the executive suite).
Here are Dan Ariely' recommendations on how to start rewarding the signal instead of noise:
I think that I need to deconstruct some of them to make them applicable to healthcare. So, here are my healthcare equivalents of culture and incentive change, so that we can start focusing on better care.1. Change the mind-set. Publicly recognize that rewarding outcomes is a bad idea, particularly for companies that deal in complex and unpredictable environments.2. Document crucial assumptions. Analyze a manager’s assumptions at the time when the decision takes place. If they are valid but circumstances change, don’t punish her, but don’t reward her, either.3. Create a standard for good decision making. Making sound assumptions and being explicit about them should be the basic condition for getting a reward. Good decisions are forward-looking, take available information into account, consider all available options, and do not create conflicts of interests.4. Reward good decisions at the time they’re made. Reinforce smart habits by breaking the link between rewards and outcomes.
1. Change the mind-set -- This applies to public reporting of never events. Tracking these on a large scale, say, city, state, country, is necessary so that we know how we are doing at not inflicting harm. However, at the level of an individual institution, there is so much variability in events such as infections, mortality, etc., that using them as a public humiliation tool is not sensible.
2. Document crucial assumptions -- We can adapt this to a healthcare setting to reflect how we build our systems to maximize prevention efforts. That is, in the setting of perpetually imperfect and oftentimes substandard evidence, in addition to tremendous inter- and intra-patient variability, a sensible evaluation of how best to approach each patient in the context of preventing complications is needed. If the evidence for interventions is valid, but the circumstances of how we understand the patient's condition change, we should not either reward or punish the provider or the institution for the associated outcome.
3. Create a standard for good decision making -- This is pretty easily adapted to our setting. Transparency, being up to date on the evidence, as well as the information on the particular patient, considering all that is reasonably available, and without conflicts of interest, are all part of the mandate for intentional quality improvement and individualized care. This also sets the criteria for what good decision support should look like.
4. Reward good decisions at the time they are made -- No translation necessary here, I think. The only thing I want to say is that there are ways other than financial to reward good performance, and we need to understand how they can be used to promote desirable behaviors among clinicians.
So, public lashings for having blood stream infections, ventilator-associated pneumonia and similar complications are not sensible. Relying on them simply reinforces the God complex in medicine and punishes the wrong link in the chain of events.
In general, it is time to let what we are learning in behavioral and cognitive sciences about what makes us tick help effect good behaviors at the bedside (and in the executive suite).
When the fuel gauge is on empty: Gadgetry at the end of life
Today's post was going to be about false positives in screening trials, but this article in the NYT derailed me. So I will talk about false positives in a future post.
The NYT article talks in general about telemonitoring of elderly and chronically ill patients as it might impact both their health and the need for more acute and intensive encounter with the healthcare system. One specific case discussed is the Mayo randomized trial of home telemonitoring, complete with physiologic measurements and adaptive leading questions based on the derived data. If I understand correctly, the data are automatically conveyed to a nurse who can then contact the patient if something seems out of the ordinary. This sounds great, except for a few minor considerations.
One of these considerations, the fact that several recent studies have failed to show any differences in clinical outcomes of patients undergoing monitoring versus usual care, is well explored in the article. And of course, the newer and better studies use newer and better technologies that do not rely on patients to call in their results, and this is why we can expect better results from the Mayo study. Maybe. Or this could be a case of rescue and auxiliary hypothesis biases, no? I guess we will see.
But there is another elephant that stands in the corner without being discussed. This elephant is of course costs. Now, if I were designing the trial, I would also try to demonstrate that these monitoring devices and protocols will save healthcare dollars by reducing hospitalization rates and the need for other acute and costly interventions. Of course, in this case you have to ask "Compared to what?" Well, of course, this is compared to our usual care. And here is where I run into a problem, and in my mind this is the place where we should be intervening.
At the risk of sounding inhumane, I wish to point out several things. The patient discussed at the very beginning of the NYT story is 94 years old and has a chronic lung disease. Later on in the story, we learn that the average age of patients enrolled in the Mayo trial is 80; and we presume that they all have at least one chronic disease that requires monitoring. What am I driving at? No, it is not death panels, but it is a sensible approach to care at the end of life. Has anyone asked the 94 year old Ms. Hofstad with chronic lung disease whether she would prefer to see the healthcare dollars spent on prolonging her life or would she prefer that these dollars were used to provide Ms. Hofstad's daughter with prenatal care and her grandkids with vaccines? For this is the true trade-off: do we continue to invent ways to keep ourselves from facing our own mortality, or do we spend the limited yet wildly escalating healthcare dollars on sensible interventions that assure health for the next generation?
If any of this sounds unethical, I would submit that it is our current blinders-on discussion that is unethical. My guess is that the elderly who were manipulated by the "death panel" rhetoric are not aware of the very real choices having to be made between going on as we are, spending shocking amounts of money for infinitesimal gains at the close of life, being subjected to heroic interventions despite their futility, and allocating this money in favor of public health interventions that will ensure a huge incremental gain in our children's and grandchildren's future. These are personal questions, but when they are wrapped in political rhetoric, they lose their personal meaning. I can tell you unequivocally that, if it came to a choice for assuring ongoing life for me versus a healthy future for my children, even today, while I am still healthy and reasonably young, I would choose the latter. Is it conceivable that Ms. Hofstad and her peers would choose otherwise? I do not thinks so. So, we need to reposition our discussion of ethics of decisions at the end of life. The choices I gave as examples are real and need to be addressed explicitly, and we all need to be aware of these trade-offs in explicit terms.
I am not interested in terminating any life that is not ready to end. However, as I always say, the number one risk for death is being born -- we have not fooled nature or evolution yet to evade this outcome. Nor, in my opinion, should we try. We should all do our best to live a healthy and full life and learn to be comfortable with the idea of our own mortality. It is our evolutionary imperative to insure the durability of our species. Electronic monitoring at the end of life, although sexy and market-friendly, is not the way to set up the future generations for health and success. And it is certainly not a way to address our fear of death, the perennial third rail of our culture. It would be more ethical and responsible to start learning more about how to do this effectively than to continue developing new gadgets to keep the vessel moving even when the gauge is on empty.
I acknowledge that this is only one person's view, and the subject is complex and emotionally jarring. I am sure there are a lot of dissenting opinions on this subject, as there should be. We need a debate, where we name all of the factors and arrive at at a global solution that comports with our personal, societal and global interests. Let us start here and now.
The NYT article talks in general about telemonitoring of elderly and chronically ill patients as it might impact both their health and the need for more acute and intensive encounter with the healthcare system. One specific case discussed is the Mayo randomized trial of home telemonitoring, complete with physiologic measurements and adaptive leading questions based on the derived data. If I understand correctly, the data are automatically conveyed to a nurse who can then contact the patient if something seems out of the ordinary. This sounds great, except for a few minor considerations.
One of these considerations, the fact that several recent studies have failed to show any differences in clinical outcomes of patients undergoing monitoring versus usual care, is well explored in the article. And of course, the newer and better studies use newer and better technologies that do not rely on patients to call in their results, and this is why we can expect better results from the Mayo study. Maybe. Or this could be a case of rescue and auxiliary hypothesis biases, no? I guess we will see.
But there is another elephant that stands in the corner without being discussed. This elephant is of course costs. Now, if I were designing the trial, I would also try to demonstrate that these monitoring devices and protocols will save healthcare dollars by reducing hospitalization rates and the need for other acute and costly interventions. Of course, in this case you have to ask "Compared to what?" Well, of course, this is compared to our usual care. And here is where I run into a problem, and in my mind this is the place where we should be intervening.
At the risk of sounding inhumane, I wish to point out several things. The patient discussed at the very beginning of the NYT story is 94 years old and has a chronic lung disease. Later on in the story, we learn that the average age of patients enrolled in the Mayo trial is 80; and we presume that they all have at least one chronic disease that requires monitoring. What am I driving at? No, it is not death panels, but it is a sensible approach to care at the end of life. Has anyone asked the 94 year old Ms. Hofstad with chronic lung disease whether she would prefer to see the healthcare dollars spent on prolonging her life or would she prefer that these dollars were used to provide Ms. Hofstad's daughter with prenatal care and her grandkids with vaccines? For this is the true trade-off: do we continue to invent ways to keep ourselves from facing our own mortality, or do we spend the limited yet wildly escalating healthcare dollars on sensible interventions that assure health for the next generation?
If any of this sounds unethical, I would submit that it is our current blinders-on discussion that is unethical. My guess is that the elderly who were manipulated by the "death panel" rhetoric are not aware of the very real choices having to be made between going on as we are, spending shocking amounts of money for infinitesimal gains at the close of life, being subjected to heroic interventions despite their futility, and allocating this money in favor of public health interventions that will ensure a huge incremental gain in our children's and grandchildren's future. These are personal questions, but when they are wrapped in political rhetoric, they lose their personal meaning. I can tell you unequivocally that, if it came to a choice for assuring ongoing life for me versus a healthy future for my children, even today, while I am still healthy and reasonably young, I would choose the latter. Is it conceivable that Ms. Hofstad and her peers would choose otherwise? I do not thinks so. So, we need to reposition our discussion of ethics of decisions at the end of life. The choices I gave as examples are real and need to be addressed explicitly, and we all need to be aware of these trade-offs in explicit terms.
I am not interested in terminating any life that is not ready to end. However, as I always say, the number one risk for death is being born -- we have not fooled nature or evolution yet to evade this outcome. Nor, in my opinion, should we try. We should all do our best to live a healthy and full life and learn to be comfortable with the idea of our own mortality. It is our evolutionary imperative to insure the durability of our species. Electronic monitoring at the end of life, although sexy and market-friendly, is not the way to set up the future generations for health and success. And it is certainly not a way to address our fear of death, the perennial third rail of our culture. It would be more ethical and responsible to start learning more about how to do this effectively than to continue developing new gadgets to keep the vessel moving even when the gauge is on empty.
I acknowledge that this is only one person's view, and the subject is complex and emotionally jarring. I am sure there are a lot of dissenting opinions on this subject, as there should be. We need a debate, where we name all of the factors and arrive at at a global solution that comports with our personal, societal and global interests. Let us start here and now.
Monday, November 22, 2010
CMS "never events": Are we rewarding the right thing?
A while ago I promised to write more about my thoughts inspired by Dan Ariely's Predictably Irrational. I still plan to do this, but in the meantime, this blog post by him made me think of medicine, and more specifically our incentives structure to prevent hospital-acquired complications (HACs). I am sure that by now everyone has heard of the "never events", so named because in the view of the Centers for Medicare and Medicaid Services (CMS) they should never happen. CMS is so convinced that they can be eradicated completely that they have eliminated payments for these complications in their effort to get hospitals to get serious about prevention. I do not have to tell you that hospitals these days are in dire financial straights, and every penny counts; so CMS is really getting them where it hurts. Here is the current list of never events, and it is likely to grow over time:
In fact, these very events are now being publicly reported as well, to help healthcare consumers navigate the quality labyrinth.
While waging an all out assault on these HACs is the absolute right thing to do, the question remains: Is it reasonable to expect zero rates of these complications? Well, for some definitely, while others I am not so sure. Take for example an object left inside the body during a surgery. Or how about amputation of the wrong limb? Or what about getting the wrong unit of blood intended for another patient? All of these examples are egregious consequences of human and systems error, and it is completely reasonable and even desirable to expect them never to happen. On the other hand, complications such as catheter-associated UTI or catheter-associated blood stream infection may not be as easily eliminated, and in fact may be impossible to eliminate completely. Why? Here is where Dan Ariely's analysis comes in.
He starts off by presenting a scenario of a soccer player kicking a ball with his eyes closed. It is clear that in the absence of intervening meddling from the wind or a playful dog (Fluffy, if you must know), the player can quickly perfect his aim despite not seeing the goal. However, it is these unpredictable events that interfere with the direction of the ball that are precisely the point, and can be applied to a business situation:
This situation is certainly analogous to the incentive structure for never events, where the hospital becomes the soccer player with its eyes closed aiming for the goal, but gets derailed by Fluffy, in this case in the persona of the patient's susceptibility to infection, say, and gets dinged for something that is completely random and not in the control of the clinician. In fact, Ariely unequivocally states something rather startling:
What is the answer? Well, here is what Ariely suggests:
I will end with Ariely's own words, since I can do no better to summarize (you can substitute appropriate healthcare related terms for the business ones):
In fact, these very events are now being publicly reported as well, to help healthcare consumers navigate the quality labyrinth.
While waging an all out assault on these HACs is the absolute right thing to do, the question remains: Is it reasonable to expect zero rates of these complications? Well, for some definitely, while others I am not so sure. Take for example an object left inside the body during a surgery. Or how about amputation of the wrong limb? Or what about getting the wrong unit of blood intended for another patient? All of these examples are egregious consequences of human and systems error, and it is completely reasonable and even desirable to expect them never to happen. On the other hand, complications such as catheter-associated UTI or catheter-associated blood stream infection may not be as easily eliminated, and in fact may be impossible to eliminate completely. Why? Here is where Dan Ariely's analysis comes in.
He starts off by presenting a scenario of a soccer player kicking a ball with his eyes closed. It is clear that in the absence of intervening meddling from the wind or a playful dog (Fluffy, if you must know), the player can quickly perfect his aim despite not seeing the goal. However, it is these unpredictable events that interfere with the direction of the ball that are precisely the point, and can be applied to a business situation:
The problem is that there’s plenty of random noise in competitive strategic decisions. Predicting where the ball will go is equivalent to deciding whether to open a chain of seafood restaurants on the Gulf Coast. The dog running off with the ball is the BP oil spill. When the board reviews the manager’s performance, they’ll focus on the failed restaurants. The stock is down. The chain lost money. Since the manager’s compensation is tied to results, he’ll incur financial penalties. To save face and appear to be taking action, the board may even fire him—thus giving up on someone who may be a good manager but had bad luck.So, in business what is rewarded or punished is not a systematic approach to decision making, but that random noise responsible for either getting the ball into the goal or alternatively diverting its trajectory. And this of course says nothing about either the soccer player or the business manager.
This situation is certainly analogous to the incentive structure for never events, where the hospital becomes the soccer player with its eyes closed aiming for the goal, but gets derailed by Fluffy, in this case in the persona of the patient's susceptibility to infection, say, and gets dinged for something that is completely random and not in the control of the clinician. In fact, Ariely unequivocally states something rather startling:
The oil spill example is an extreme case. In the real world, the random noise is often more subtle and various—a hundred little things rather than one big thing. But the effect is the same. Rewarding and penalizing leaders based on outcomes overestimates how much variance people actually control. (This works both ways: Just as good managers can suffer from bad outcomes not of their own making, bad managers can be rewarded for good outcomes that occur in spite of their ineptitude.) In fact, the more unpredictable an environment becomes, the more an outcomes-based approach ends up rewarding or penalizing noise. [emphasis mine]Unpredictable you say? What can be more unpredictable and filled with uncertainty than the interaction of human biology with disease and external interventions? This repositioning of the argument really confirms for me that demanding never events is really just window dressing. For a long time there has been a joke among health services researchers that, over the next few years, these events will disappear, but not because these events actually disappear. Sophisticated hospital coders will simply stop putting these outcomes in their documentation to the payers. And will this achieve better care or just better looking documentation? I think you know what I am driving at.
What is the answer? Well, here is what Ariely suggests:
We can’t entirely avoid outcome-based decisions. Still, we can reduce our reliance on stochastic outcomes. Here are four ways companies can create more-sound reward systems.
1. Change the mind-set. Publicly recognize that rewarding outcomes is a bad idea, particularly for companies that deal in complex and unpredictable environments.
2. Document crucial assumptions. Analyze a manager’s assumptions at the time when the decision takes place. If they are valid but circumstances change, don’t punish her, but don’t reward her, either.
3. Create a standard for good decision making. Making sound assumptions and being explicit about them should be the basic condition for getting a reward. Good decisions are forward-looking, take available information into account, consider all available options, and do not create conflicts of interests.
4. Reward good decisions at the time they’re made. Reinforce smart habits by breaking the link between rewards and outcomes.And even though this advice is aimed at business leaders, it can be easily adapted to medicine. If we heed this warning, we may avoid having to wring our hands in another 10 years about the "unintended consequence" of losing critical data needed to understand how we are really doing with improving healthcare outcomes.
I will end with Ariely's own words, since I can do no better to summarize (you can substitute appropriate healthcare related terms for the business ones):
Our focus on outcomes is understandable. When a company loses money, people demand that heads roll, even if the changes are more about assuaging shareholders than sound management. Moreover, measuring outcomes is relatively easy to do; decision-making–based reward systems will be more complex. But as I’ve said before, “It’s hard” is a terrible reason not to do something. Especially when that something can help reward and retain the people best able to help you grow your business.
Sunday, November 21, 2010
Journalism or advertising? "The Health Show" on NPR
Addendum 11/22/10:
I want to be very clear that I very much appreciate excellent health reporting by Julie Rovner, JoAnne Silberner, Scott Hensley and other NPR healthcare reporters. What concerns me about this show is that it is popularized coverage, and, as such, may reach a broad audience who does not have the tools to recognize critical gaps in the story.
I love NPR! We are lucky enough to have 2 local NPR stations to choose from, WFCR and WAMC. I love everything about them -- their critical approach to politics, their intellectual curiosity and their local flavor. What I sometimes do not love is their coverage of health news.
Case in point is tonight's broadcast of "The Health Show". I was driving on one of our particularly windy roads while listening to the first story of the show covering the NCI's NLST, and almost drove off the road! I was glad that it was dark, so no one could see the crazy lady behind the wheel yelling back at the radio. Why was I yelling? Here is why.
The story was of course about the staggering success of NLST. The guest interviewed was Dr. Regina Vidaver, the Executive Director of the National Lung Cancer Partnership, a group focused on understanding gender differences in lung cancer. The initial conversation focused on the NLST cancer mortality data, where the enthusiastic host threw a give-away to the equally enthusiastic guest about the main finding. The guest ran with it, breathlessly citing the 20% reduction in cancer deaths. In all fairness, she did not fall into the host's trap of inference as to the cause of this reduction, assumed by him to be due to early detection, as she responded that these data have not been analyzed yet or reported in peer-reviewed literature. Dr. Vidaver further intimated that this is a very promising break-through, sure to change the outcomes of lung cancer among heavy smokers. She even compared it to breast cancer mortality reduction due to mammography screening. What rock has she been living under?
Throughout the interview, I kept waiting for the host to ask some critical questions, like what was the actual (absolute) reduction in mortality? Or how many patients would need to be screened annually and for how long to prevent one death? Or how much will it cost to prevent one death? Or what is the risk and what are the implications of a false positive result (these data have been reported, and it looks like 1 out of 4 screened patients may have a false positive test)? And what about how this testing compares to the costs and effectiveness of smoking prevention and cessation efforts? These are pretty elementary concepts which I discussed at great length here and here. No, none of these issues was explored, just the awe-struck host feeding soft questions to the guest. I swear, I thought I was listening to an infomercial! This is journalism? And on NPR? Come on!
But the most peculiar part of the interview came later. Here the host and the guest emphasized that other potential causes of lung CA exist and cannot be ignored, like radon and second-hand smoke. Strangely, there was no mention of asbestos or other occupational or chemical exposures. Don't take me wrong, these are important causes. But what do they have to do with the NLST data? Were they implying that everyone should undergo screening and not just those with heavy smoking history, since we do not know always what exposures other than smoking may be present? Furthermore, the big elephant in this interview was the lack of mention that 85% of all lung cancer is caused by smoking -- why not cite this startling statistic? Not compelling enough? Is it not amazing that, if every smoker quit, we could avoid about 190,000 new cases of lung CA in the US annually? Not to mention all the other disease caused by this poison.
But instead of pointing out the potential advantages of public health interventions aimed at smoking cessation, NPR decided to give easy air time to a shiny new technology, holding great promise for the uninformed masses and for the market, but fraught with untold expense and complications. Is this responsible journalism? NPR and WAMC, you can and should do better than this!
Top 5 this week
The top five posts this week are as follows:
#5: Unidirectional skepticism
#4: Some implications of biologic plausibility
#3: The "but" is not the message
#2: Slow medicine
And the #1 post this week is... (drum roll, please)... Patient empowerment: A tango worth dancing
Thank you for your reads and comments!
#5: Unidirectional skepticism
#4: Some implications of biologic plausibility
#3: The "but" is not the message
#2: Slow medicine
And the #1 post this week is... (drum roll, please)... Patient empowerment: A tango worth dancing
Thank you for your reads and comments!
Saturday, November 20, 2010
Slow medicine
I don't know if you remember, but back in March our Earth started to spin faster. The devastating earthquake in Chile shifted our axis to create shorter days. Not that much shorter -- we are talking about a 1.26-microsecond reduction. Not particularly noticeable. But I have to wonder if our ever-increasing pace of life is not merely emblematic of these periodic but frequent cataclysmic accelerations of the planet.
What a cliche it is to say that we live in a speeding up 24/7 world, where, if you do no keep up, you drop off. We have fast cars, fast communications, fast food, and yes, fast medicine. This fast medicine concept ties together many of the ideas I have discussed here over the last few days and weeks.
It is most peculiar to me that, even in the Communist country of my birth, early on I learned the expression "time is money" from my father. It certainly did not resonate there; in fact, it did not begin to make sense until I was an adult in the US and beginning to understand what makes our economy tick. And indeed, time in our society can be counted off in dollars. Over the past 60 years, the American dream of a suburban house, 2 cars and 2.5 kids, a 40-hour-a-week job, and time on the weekends with the family, has mutated into an endless work day, constant accessibility and distant and loose connections. This is not all bad necessarily, but the promise of more efficient workplace resulting from the proliferation of technology has been forgotten. Instead, this technology, shiny and sexy and laden with the symbology of status, tethers us to perpetual productivity. And the expectation of these productivity increases accompanied by reduced production costs is what drives our economic growth. But at what personal and societal costs?
Aside from the rampant breakdown of communities, many other emerging phenomena are a part of the package. Take the obesity epidemic, for example. We can certainly continue the debate about the factors contributing to it, we can continue our search for the irrefutable smoking gun, but let's be honest: how can our fast food culture not be a major contributor? Of course it is. Along with the sedentary lifestyle and the culturally sanctioned pursuit of fast satisfaction, the biology is indisputable: cheap and accessible highly caloric food and drinks consumed in excess without the balance of physical expenditures -- bingo, the math adds up to this perfect storm. Evidence (and common sense, I might add) suggests that slow food cooked at home may be an antidote to the overdose of the toxic "nutrition" foisted onto the nation, especially the young people. But, in the words of my niece, "we don't have time for Minute rice!" We need to continue running on this treadmill that our lives have become, so as not to miss the opportunity for the carrot at the end of it. Or are we just hallucinating the carrot?
And all of this rushing about has naturally penetrated medicine. Since it is just another market,where productivity drives someone's bottom line, the treadmill will surely continue to speed up. Yet, here, I talked extensively about why the incredible shrinking appointment is such a bad idea: most real issues come at the end of the 15 minutes, when the patient's or the doctor's hand is beginning to turn the door handle. And fortuitously or not, this motif has been carried by other bloggers like Dr. Synonymous here, a dedicated family physician in Columbus, OH, trying to balance good medicine with staying in business. He poignantly describes his every-day struggles to fit his patients' seven to eleven problems into a four-problem widget that he is encouraged to produce. It is doctors like Dr. Synonymous that could rein in our catastrophic healthcare spending just by being given time and space to focus on the patient without the pressures of ever-increasing production. And then Kevin Pho, better known as KevinMD, healthcare blogger royalty, on his blog eloquently connects the dots between the widgetry of the medical appointments and some of our most pressing public health challenges. Here is what he says:
What is the answer? Even when I was in practice, I was a good diagnostician, but when it came to treatment, it did not have that much interest to me. So here, just as in practice, I find myself more interested in defining the problem and letting others help me find the solution. This is my long-winded way of admitting that I do not have the perfect answer. However, patient empowerment is one of those answers, where at the personal level the patients need to understand how to manage this "microwave" medical encounter to the best of their needs. At the policy level, patients and doctors need to pool forces and start naming the problem before the "but" subverts the discussion. And it may just be that the best solution is to restore medicine's social contract and to wrestle medicine out of the clutches of market forces back into the therapeutic arena.
Medicine will never return to its prior rhythm, but we must strive to get it to a better place, where both patients and clinicians have the time to address the obvious. The fast model of medicine, much like fast food, is creating a nation of illness and discontent. Just as in the food movement, let's start creating an infrastructure where our healthcare professionals can practice slow medicine, having the time to address our individual issues thoroughly and completely and in a manner that promotes health rather than perpetuate disease.
What a cliche it is to say that we live in a speeding up 24/7 world, where, if you do no keep up, you drop off. We have fast cars, fast communications, fast food, and yes, fast medicine. This fast medicine concept ties together many of the ideas I have discussed here over the last few days and weeks.
It is most peculiar to me that, even in the Communist country of my birth, early on I learned the expression "time is money" from my father. It certainly did not resonate there; in fact, it did not begin to make sense until I was an adult in the US and beginning to understand what makes our economy tick. And indeed, time in our society can be counted off in dollars. Over the past 60 years, the American dream of a suburban house, 2 cars and 2.5 kids, a 40-hour-a-week job, and time on the weekends with the family, has mutated into an endless work day, constant accessibility and distant and loose connections. This is not all bad necessarily, but the promise of more efficient workplace resulting from the proliferation of technology has been forgotten. Instead, this technology, shiny and sexy and laden with the symbology of status, tethers us to perpetual productivity. And the expectation of these productivity increases accompanied by reduced production costs is what drives our economic growth. But at what personal and societal costs?
Aside from the rampant breakdown of communities, many other emerging phenomena are a part of the package. Take the obesity epidemic, for example. We can certainly continue the debate about the factors contributing to it, we can continue our search for the irrefutable smoking gun, but let's be honest: how can our fast food culture not be a major contributor? Of course it is. Along with the sedentary lifestyle and the culturally sanctioned pursuit of fast satisfaction, the biology is indisputable: cheap and accessible highly caloric food and drinks consumed in excess without the balance of physical expenditures -- bingo, the math adds up to this perfect storm. Evidence (and common sense, I might add) suggests that slow food cooked at home may be an antidote to the overdose of the toxic "nutrition" foisted onto the nation, especially the young people. But, in the words of my niece, "we don't have time for Minute rice!" We need to continue running on this treadmill that our lives have become, so as not to miss the opportunity for the carrot at the end of it. Or are we just hallucinating the carrot?
And all of this rushing about has naturally penetrated medicine. Since it is just another market,where productivity drives someone's bottom line, the treadmill will surely continue to speed up. Yet, here, I talked extensively about why the incredible shrinking appointment is such a bad idea: most real issues come at the end of the 15 minutes, when the patient's or the doctor's hand is beginning to turn the door handle. And fortuitously or not, this motif has been carried by other bloggers like Dr. Synonymous here, a dedicated family physician in Columbus, OH, trying to balance good medicine with staying in business. He poignantly describes his every-day struggles to fit his patients' seven to eleven problems into a four-problem widget that he is encouraged to produce. It is doctors like Dr. Synonymous that could rein in our catastrophic healthcare spending just by being given time and space to focus on the patient without the pressures of ever-increasing production. And then Kevin Pho, better known as KevinMD, healthcare blogger royalty, on his blog eloquently connects the dots between the widgetry of the medical appointments and some of our most pressing public health challenges. Here is what he says:
These are not assertions that require big studies or demonstration projects -- this is the knowledge we gain from living: relationships are everything, and relationships take time to build. And time is what continues to erode in the office encounter.
That’s a valid point. When it comes to their own children, it’s unlikely that trumpeting public health fears is going to significantly sway parents’ opinion, especially if they come in believing that vaccines are associated with autism.A parallel situation is with antibiotic overuse. Again, public health arguments mostly fall upon deaf ears in the exam room, as there are many patients who believe that upper respiratory symptoms require an antibiotic.What’s the answer? More time to spend with patients, for one. And second, Dr. Parikh alludes to the fact that most doctors don’t receive adequate training when it comes to vaccines: “If there is one thing Sears gets right, it is the fact that doctors need more education about vaccine science from the get-go.” [emphasis mine]
What is the answer? Even when I was in practice, I was a good diagnostician, but when it came to treatment, it did not have that much interest to me. So here, just as in practice, I find myself more interested in defining the problem and letting others help me find the solution. This is my long-winded way of admitting that I do not have the perfect answer. However, patient empowerment is one of those answers, where at the personal level the patients need to understand how to manage this "microwave" medical encounter to the best of their needs. At the policy level, patients and doctors need to pool forces and start naming the problem before the "but" subverts the discussion. And it may just be that the best solution is to restore medicine's social contract and to wrestle medicine out of the clutches of market forces back into the therapeutic arena.
Medicine will never return to its prior rhythm, but we must strive to get it to a better place, where both patients and clinicians have the time to address the obvious. The fast model of medicine, much like fast food, is creating a nation of illness and discontent. Just as in the food movement, let's start creating an infrastructure where our healthcare professionals can practice slow medicine, having the time to address our individual issues thoroughly and completely and in a manner that promotes health rather than perpetuate disease.
Thursday, November 18, 2010
Patient empowerment: A tango worth dancing
I like to poke fun at real estate agents (please, forgive me if you are one, it is all in good fun). My experience has been that, despite what I describe as my preferences, they always end up showing me what they have, even if it does not bear the remotest resemblance to what I need. This holds true for politicians, with this cardinal rule: always answer the question you want to answer, rather than the one being asked. Well, now that I think about it, it is also true for modern medicine. Here is how.
This morning I attended the annual fundraising breakfast for an organization that started locally, but is spreading nationally and even internationally. The group is MotherWoman, and it arose from a realization that women's post-partum needs were not being met. At the regional level, women suffering post-partum depression had no resources available to them, and the local clinicians were not clued in to the problem to the point where they could offer targeted help. And although the organization has grown and matured around issues of parenting in general, they are still known for their robust community outreach to help manage PPD.
So, every year they have a fundraising breakfast, and every year I set a limit for the sum I will write in that box on the check, and every year, after hearing inspirational stories of real women and families, I go over this limit. This year was no different. The speakers were fantastic -- passionate, committed, authentic. Sharon Lerner, the journalist and author of The War on Moms, was a featured speaker. But the most touching of all was the talk by a young mother, followed by one by her husband, about their family's struggle with profound dark and shattering PPD. Aside form the fact that there was not a dry eye in the audience, the story had yet another effect, on me specifically: it clarified for me the importance of empowering mothers, fathers, families and all patients to advocate for themselves. The story was one of missed opportunities to listen to, to connect with, to help someone whose life was suddenly too heavy to carry. Instead of offering individual care and support, the woman was prescribed a one-size fit-all fix, which she was not willing to accept. Yet the healthcare system failed to offer a viable alternative. Just as in the case of the real estate agent and the politician, the property shown and the question answered were not this woman's. Instead, they were generic solutions driven by our increasingly widget-oriented approach to healthcare.
She and her family did eventually get the help they needed, not the least of which came from MotherWoman, and she is well on her way out of the jungle of PPD. And just as this family made clear, over and over again I hear people tell me that they do not blame their healthcare providers, they do not consider them evil, and they actually appreciate the efforts made by them on their behalf. But these efforts fall short when we are forced to measure individuals with a population-based yardstick, leaving both the patients and the physicians frustrated.
The way we derive evidence for our practices needs to change. There are many underutilized tools already available to help us understand inter-individual variations, and there are many more that need to be developed and used. But as in any relationship, patients need to learn to speak up and make their needs heard. We need to develop a common vocabulary so that clinicians can become aware of our needs and be sensitive to them.
As I tell my children when they bicker and come to me complaining about each other, it takes two to tango. Physicians are busier than ever, we live in the era of the incredible shrinking appointment, and the proliferation of gadgetry and other pressures on the doctors' attention and time is crushing. Just as we are not afraid to let the real estate agent know to change course, just as we demand that politicians answer our questions, so in this the patients need to learn to advocate for themselves. This is surely a culture shift. Yet this is one dance that is worth performing well.
Update 11/19/2010:
I encourage you to go here to read Sharon Lerner's remarks.
This morning I attended the annual fundraising breakfast for an organization that started locally, but is spreading nationally and even internationally. The group is MotherWoman, and it arose from a realization that women's post-partum needs were not being met. At the regional level, women suffering post-partum depression had no resources available to them, and the local clinicians were not clued in to the problem to the point where they could offer targeted help. And although the organization has grown and matured around issues of parenting in general, they are still known for their robust community outreach to help manage PPD.
So, every year they have a fundraising breakfast, and every year I set a limit for the sum I will write in that box on the check, and every year, after hearing inspirational stories of real women and families, I go over this limit. This year was no different. The speakers were fantastic -- passionate, committed, authentic. Sharon Lerner, the journalist and author of The War on Moms, was a featured speaker. But the most touching of all was the talk by a young mother, followed by one by her husband, about their family's struggle with profound dark and shattering PPD. Aside form the fact that there was not a dry eye in the audience, the story had yet another effect, on me specifically: it clarified for me the importance of empowering mothers, fathers, families and all patients to advocate for themselves. The story was one of missed opportunities to listen to, to connect with, to help someone whose life was suddenly too heavy to carry. Instead of offering individual care and support, the woman was prescribed a one-size fit-all fix, which she was not willing to accept. Yet the healthcare system failed to offer a viable alternative. Just as in the case of the real estate agent and the politician, the property shown and the question answered were not this woman's. Instead, they were generic solutions driven by our increasingly widget-oriented approach to healthcare.
She and her family did eventually get the help they needed, not the least of which came from MotherWoman, and she is well on her way out of the jungle of PPD. And just as this family made clear, over and over again I hear people tell me that they do not blame their healthcare providers, they do not consider them evil, and they actually appreciate the efforts made by them on their behalf. But these efforts fall short when we are forced to measure individuals with a population-based yardstick, leaving both the patients and the physicians frustrated.
The way we derive evidence for our practices needs to change. There are many underutilized tools already available to help us understand inter-individual variations, and there are many more that need to be developed and used. But as in any relationship, patients need to learn to speak up and make their needs heard. We need to develop a common vocabulary so that clinicians can become aware of our needs and be sensitive to them.
As I tell my children when they bicker and come to me complaining about each other, it takes two to tango. Physicians are busier than ever, we live in the era of the incredible shrinking appointment, and the proliferation of gadgetry and other pressures on the doctors' attention and time is crushing. Just as we are not afraid to let the real estate agent know to change course, just as we demand that politicians answer our questions, so in this the patients need to learn to advocate for themselves. This is surely a culture shift. Yet this is one dance that is worth performing well.
Update 11/19/2010:
I encourage you to go here to read Sharon Lerner's remarks.
Wednesday, November 17, 2010
Some implications of biologic plausibility
Ever since my... ahem... skirmish... with the folks over at the SBM, I have been contemplating the issue of biologic plausibility. They contend that our tax dollars are wasted by being allocated to the NCCAM to pursue research into CAM. Their reasoning is that there is no biological plausibility to any of it having any therapeutic effect. Now, this is a big bite to swallow. As I have said before there is CAM and then there is CAM. CAM seems to be a convenient wastebasket of modalities that we feel justified in bashing as "woo" since there is limited scientific evidence behind them. But really, I am more willing to give acupuncture and massage the benefit of the doubt than, say, healing crystals (even though I confess I really like rocks!).
So, what of this biologic plausibility, and who came up with it anyway? And is it truly fiscally irresponsible, and possibly even unethical, to test interventions that do not fit our biological plausibility criteria? As a corollary, is there a level of our understanding of biology that makes testing equally wasteful or even unethical? And finally, should plausibility of benefit and harm be required to reach the same evidentiary bar?
For the definition of biological plausibility we apparently thank the milestone 1964 Surgeon General's report linking smoking to cancer. This report was the first official US government document to state that there was enough evidence to implicate cigarette smoking in the rise in lung cancer and cancer deaths. Since the limitations of observational research were used by the critics for decades to derail this definitive statement, the report itself does a nice job laying out the methodologic considerations and the need to rely on the Bradford-Hill criteria. It was in the "coherence" criterion that biologic plausibility entered the picture.
A quick check of my favorite crowd-sourced information site, the Wikipedia, uncovers this treasure from Sir Bradford Hill himself:
Now, on to the question of whether there exist relationships with such high biologic plausibility that they do not require irrefutable proof. Well, how about tobacco and its health effects? How about radiation exposure? Now, how about what we know today about the evolution of microbial resistance to antibiotics? Is it enough that the biologic plausibility for ill-effects of antibiotics in our food chain is strong? Can we now stop the madness? If my colleagues over at SBM are given to the same logic, they would say yes to this. However, extrapolating from this post about organic food production, I somehow think that they would not. So, I am guessing that, although they believe that lack of biologic plausibility should preclude attempts at study, they will nevertheless be reluctant to set a threshold for biologic plausibility that might obviate the need for further research. I am just guessing, and would love to hear what they really think.
And finally, what of the plausibility of benefit vs. that of harm? Should our bar for biologic plausibility for harm be lower than that for benefit? Well, the question really boils down to this: How many bodies do we need to see lying in the streets before we concede that there is a problem? My point is that we Americans have a hard time subscribing to the precautionary principle, applied generously in other parts of the world. If we were a tad less reckless with our need for irrefutable evidence, how many decades of equivocation about tobacco and cancer would we have avoided? How many lives might have been saved? Biologic plausibility for the connection was known even in the 1930s, yet it took another three decades for us to act. What are we obfuscating today that will come back to bite us (and our children) tomorrow? Could it be the cynical injection of doubt that our food production system is causing irreversible damage to us and life around us?
So, what I am saying is that biologic plausibility has several facets. We have to admit humbly that its assumption relies on our necessarily incomplete knowledge, and denying this may prevent us from awe-inspiring discoveries that will advance science in leaps. However, if we feel strongly about the need for it in order to justify our research allocation, some careful soul searching is in order for those thresholds of probability, especially of harm, where we may admit that science makes us sure enough, and, instead of awaiting perfect evidence, we must act promptly.
So, what of this biologic plausibility, and who came up with it anyway? And is it truly fiscally irresponsible, and possibly even unethical, to test interventions that do not fit our biological plausibility criteria? As a corollary, is there a level of our understanding of biology that makes testing equally wasteful or even unethical? And finally, should plausibility of benefit and harm be required to reach the same evidentiary bar?
For the definition of biological plausibility we apparently thank the milestone 1964 Surgeon General's report linking smoking to cancer. This report was the first official US government document to state that there was enough evidence to implicate cigarette smoking in the rise in lung cancer and cancer deaths. Since the limitations of observational research were used by the critics for decades to derail this definitive statement, the report itself does a nice job laying out the methodologic considerations and the need to rely on the Bradford-Hill criteria. It was in the "coherence" criterion that biologic plausibility entered the picture.
A quick check of my favorite crowd-sourced information site, the Wikipedia, uncovers this treasure from Sir Bradford Hill himself:
It will be helpful if the causation we suspect is biologically plausible. But this is a feature I am convinced we cannot demand. What is biologically plausible depends upon the biological knowledge of the day. To quote again from my Alfred Watson Memorial Lecture [1962], there was
- "…no biological knowledge to support (or to refute) Pott’s observation in the 18th century of the excess of cancer in chimney sweeps. It was lack of biological knowledge in the 19th that led to a prize essayist writing on the value and the fallacy of statistics to conclude, amongst other “absurd” associations, that 'it could be no more ridiculous for the strange who passed the night in the steerage of an emigrant ship to ascribe the typhus, which he there contracted, to the vermin with which bodies of the sick might be infected.' And coming to nearer times, in the 20th century there was no biological knowledge to support the evidence against rubella."
In short, the association we observe may be one new to science or medicine and we must not dismiss it too light-heartedly as just too odd. As Sherlock Holmes advised Dr. Watson, "when you have eliminated the impossible, whatever remains, however improbable, must be the truth."[1]Aha, so biologic plausibility is a function of the state of our current knowledge, today. By this litmus test, Marshall and Warren should have been laughed out of all funding agencies. Instead, they rewrote our understanding of what can live in the stomach, and how a microorganism can cause peptic ulcer disease and stomach cancer. And got themselves a cool Nobel to boot. So much for the ethics and finances of biologic plausibility informing meaningful research.
Now, on to the question of whether there exist relationships with such high biologic plausibility that they do not require irrefutable proof. Well, how about tobacco and its health effects? How about radiation exposure? Now, how about what we know today about the evolution of microbial resistance to antibiotics? Is it enough that the biologic plausibility for ill-effects of antibiotics in our food chain is strong? Can we now stop the madness? If my colleagues over at SBM are given to the same logic, they would say yes to this. However, extrapolating from this post about organic food production, I somehow think that they would not. So, I am guessing that, although they believe that lack of biologic plausibility should preclude attempts at study, they will nevertheless be reluctant to set a threshold for biologic plausibility that might obviate the need for further research. I am just guessing, and would love to hear what they really think.
And finally, what of the plausibility of benefit vs. that of harm? Should our bar for biologic plausibility for harm be lower than that for benefit? Well, the question really boils down to this: How many bodies do we need to see lying in the streets before we concede that there is a problem? My point is that we Americans have a hard time subscribing to the precautionary principle, applied generously in other parts of the world. If we were a tad less reckless with our need for irrefutable evidence, how many decades of equivocation about tobacco and cancer would we have avoided? How many lives might have been saved? Biologic plausibility for the connection was known even in the 1930s, yet it took another three decades for us to act. What are we obfuscating today that will come back to bite us (and our children) tomorrow? Could it be the cynical injection of doubt that our food production system is causing irreversible damage to us and life around us?
So, what I am saying is that biologic plausibility has several facets. We have to admit humbly that its assumption relies on our necessarily incomplete knowledge, and denying this may prevent us from awe-inspiring discoveries that will advance science in leaps. However, if we feel strongly about the need for it in order to justify our research allocation, some careful soul searching is in order for those thresholds of probability, especially of harm, where we may admit that science makes us sure enough, and, instead of awaiting perfect evidence, we must act promptly.
Tuesday, November 16, 2010
The "but" is not the message
Two telling patient encounters still stand out in my memory, one from before medical school and one from my practice. The first one was at a clinic that I visited as a mentee to a clinician, where a young woman came in for a routine physical. After the talking and the physical were done, as she was standing by the door about to turn the handle, she looked at my mentor and, with tears in her eyes proclaimed: "I am worried that I may be pregnant!" The second event that I recall was when I was seeing a relatively new asthma patient, an upper-middle-class woman in her 30s with a husband and two kids. When we were ostensibly done with her medical issues, and as she was getting up off the examining table to leave, she suddenly broke down and revealed her concern for her husband's health.
Both of these encounters stuck with me as an illustration of how the human psyche drags after us into the office where one complaint per appointment is the rule of the day. And this is where studies like the one discussed by Jane Brody in yesterday's edition of the New York Times have a certain, shall we say, "duh" factor. The patient wants to feel good, really? Is this really news to any clinician? And yes, different patients will have different utilities for what their diseases or treatments are doing for them. And yes, some people are more resilient than others. And yes, some people will rely in the doctor's expertise, while others are more willing to be empowered. But in the end, is it really necessary to spend dollars on studies that confirm all of these observations?
But here is what really got me, this one small paragraph in this 600-word or so essay:
To introduce the "but" is to deny the gravity of what is happening. The "but" diminishes any chances of a meaningful conversation about the real barriers to what we all know is good patient care. The "but" assumes a petulant contempt for the obvious on the part of the physician willfully avoiding the messiness of anything that is not lucrative. The "but" dilutes the important message: WE NEED MORE TIME!!! That is the message, not that we need to pit groups against each other with the "but"!
Now, the problem is huge and is likely to get worse. But... sitting on our hands and getting angry at the evil medical establishment for not taking the time to deal with our quality of life in the shrinking appointments will not change the system. People are people, and our psyche, no matter how hard we work at leaving it in the waiting room, will invariably follow us into the exam room. And all important emotional stuff comes out at the end, when the time has already run out, when the patient or the doctor is about to turn the door handle.
So, while the problem is clear, the solution is not. Nevertheless, the "but" is a way to evade having to find the real solutions. Let us keep the "but" out of the conversation and focus on what really needs to change.
Both of these encounters stuck with me as an illustration of how the human psyche drags after us into the office where one complaint per appointment is the rule of the day. And this is where studies like the one discussed by Jane Brody in yesterday's edition of the New York Times have a certain, shall we say, "duh" factor. The patient wants to feel good, really? Is this really news to any clinician? And yes, different patients will have different utilities for what their diseases or treatments are doing for them. And yes, some people are more resilient than others. And yes, some people will rely in the doctor's expertise, while others are more willing to be empowered. But in the end, is it really necessary to spend dollars on studies that confirm all of these observations?
But here is what really got me, this one small paragraph in this 600-word or so essay:
Of course, everyone knows that a doctor’s time these days is limited. But for medical care to be delivered efficiently and economically, assessing health-related quality of life is an essential element that can help doctors identify therapy that is counterproductive or ineffective or needs to be modified.Note especially the leading sentence, "Of course, everyone knows that a doctor's time these days is limited". Let's stop here. As we sit and ponder it in silence, we just know that there is a big gigantic "but" that is about to hit us on the head. And sure enough, it does -- how predictable. But it is this sentence alone that should be printed in bold letters and stand alone, so that everyone -- researchers, patients, administrators, government bureaucrats and other pertinent parties -- stop and really think about the ever-growing crevasse between what is good for the patient, what is good for the doctor and what is good for the society and the reality of our widget-producing healthcare system.
To introduce the "but" is to deny the gravity of what is happening. The "but" diminishes any chances of a meaningful conversation about the real barriers to what we all know is good patient care. The "but" assumes a petulant contempt for the obvious on the part of the physician willfully avoiding the messiness of anything that is not lucrative. The "but" dilutes the important message: WE NEED MORE TIME!!! That is the message, not that we need to pit groups against each other with the "but"!
Now, the problem is huge and is likely to get worse. But... sitting on our hands and getting angry at the evil medical establishment for not taking the time to deal with our quality of life in the shrinking appointments will not change the system. People are people, and our psyche, no matter how hard we work at leaving it in the waiting room, will invariably follow us into the exam room. And all important emotional stuff comes out at the end, when the time has already run out, when the patient or the doctor is about to turn the door handle.
So, while the problem is clear, the solution is not. Nevertheless, the "but" is a way to evade having to find the real solutions. Let us keep the "but" out of the conversation and focus on what really needs to change.
Monday, November 15, 2010
Unidirectional skepticism
I thought I had coined that phrase. I have used it to refer to our tendency to examine ideas that are not aligned with our views of reality with less rigor than those that confirm it. It turns out that I am not the first to notice this phenomenon. In this Harper's article, Gary Greenberg uses the following quote from Mario Beauregard, a neuroscientist at the University of Montreal, writing about the seat of the "self":
This has got me thinking about a couple of things. Now, I am a big fan of neurobiology and the burgeoning field of research that it represents. We understand what goes on in the brain so much better now at the molecular level than we did, say, even 20 years ago. But what I am struck by is the comfort that this knowledge gives us about ideas of human behavior we had understood with lesser granularity in the prior era. For example, all parents have appreciated for millennia that teenage behavior is characterized by disinhibition of the higher self, if you will. Now we can say this in scientific lingo, that the area of the prefrontal cortex responsible for executive function lags in development behind other areas of the brain, as demonstrated in fMRI studies. Or how about the evidence from advanced neuroimaging that doing stuff that benefits our community lights up areas that correspond to happiness? We knew this before, only not in these words: we just had an idea that being a part of a community made us feel good. And those of us who subscribe to evolution can even come up with an explanation for why we should have developed this way.
Yet, aside from just gaining fascinating knowledge, we derive an odd sense of satisfaction from having our prior ideas, arrived through experience, observation and philosophical ruminations, confirmed by what we consider to be a more bona fide technique of science. The corollary to this is that, because we are so committed to the scientific method above all other possible ways of knowing, we may also be all too willing to discard rapidly closely-held notions that are not supported by science. But since science is ever-evolving and rather imprecise, in some areas more so than in others, are we always justified in such prompt disposal of prior beliefs?
In the clinical world we often cite examples of when our intuition was wrong about some disease or another, and only after doing well controlled research studies were we able to arrive at the real understanding of the situation. But how often is it just our willingness to yield to what we think is scientifically sound at the moment? Is it possible that this unidirectional skepticism fueled by the cognitive bias in favor of new science, may not turn out to be the most efficient way to accumulate knowledge?
I do not know the answer to this question, as I am as guilty as my peers of falling in love with new scientific knowledge. But I also enjoy thinking about the nature of knowledge in general, and the many different ways of knowing. Are the materialism of science and other epistemologies mutually exclusive? I hope not.
The culture of popular science is one of unidirectional skepticism... It is skeptical of any idea that spirituality corresponds to something outside ourselves, but surprisingly gullible about any reductionist explanation for it.Still, I think that my use of the term is somewhat broader, not simply alluding to the popular science, but also to professional science, and not only to the neurobiology of self. This idea goes hand in hand with the cognitive biases we are subject to.
This has got me thinking about a couple of things. Now, I am a big fan of neurobiology and the burgeoning field of research that it represents. We understand what goes on in the brain so much better now at the molecular level than we did, say, even 20 years ago. But what I am struck by is the comfort that this knowledge gives us about ideas of human behavior we had understood with lesser granularity in the prior era. For example, all parents have appreciated for millennia that teenage behavior is characterized by disinhibition of the higher self, if you will. Now we can say this in scientific lingo, that the area of the prefrontal cortex responsible for executive function lags in development behind other areas of the brain, as demonstrated in fMRI studies. Or how about the evidence from advanced neuroimaging that doing stuff that benefits our community lights up areas that correspond to happiness? We knew this before, only not in these words: we just had an idea that being a part of a community made us feel good. And those of us who subscribe to evolution can even come up with an explanation for why we should have developed this way.
Yet, aside from just gaining fascinating knowledge, we derive an odd sense of satisfaction from having our prior ideas, arrived through experience, observation and philosophical ruminations, confirmed by what we consider to be a more bona fide technique of science. The corollary to this is that, because we are so committed to the scientific method above all other possible ways of knowing, we may also be all too willing to discard rapidly closely-held notions that are not supported by science. But since science is ever-evolving and rather imprecise, in some areas more so than in others, are we always justified in such prompt disposal of prior beliefs?
In the clinical world we often cite examples of when our intuition was wrong about some disease or another, and only after doing well controlled research studies were we able to arrive at the real understanding of the situation. But how often is it just our willingness to yield to what we think is scientifically sound at the moment? Is it possible that this unidirectional skepticism fueled by the cognitive bias in favor of new science, may not turn out to be the most efficient way to accumulate knowledge?
I do not know the answer to this question, as I am as guilty as my peers of falling in love with new scientific knowledge. But I also enjoy thinking about the nature of knowledge in general, and the many different ways of knowing. Are the materialism of science and other epistemologies mutually exclusive? I hope not.
Saturday, November 13, 2010
Top 5 this week
Top 5 posts on Healthcare, etc. this week are:
#5 More thoughts on lung cancer screening
#4 Manipulating science
#3 Death panels and mammography: Only the beginning
#2 CT screening for lung CA: an epidemiology primer
#1 post this week is (drum roll, please)... Could our application of EBM be unethical?
Thanks for interesting discussions for all those who have contributed!
#5 More thoughts on lung cancer screening
#4 Manipulating science
#3 Death panels and mammography: Only the beginning
#2 CT screening for lung CA: an epidemiology primer
#1 post this week is (drum roll, please)... Could our application of EBM be unethical?
Thanks for interesting discussions for all those who have contributed!
Friday, November 12, 2010
Is it the science or is it the message?
As you know, I have been thinking a lot about cognitive biases lately. Apropos this, I have had this nagging thought that even smart people (I flatter myself by including myself in this group) cannot escape this trap. What sent me down this rabbit hole is a tweet I saw in my stream from someone whom I respect very much, a science writer of the highest caliber with an international reputation. This person said:
The link is to a radio interview with Devra Davis, whom I have mentioned on several occasions on this blog. I read her book on cancer with great interest, and the history that she told in a measured and well documented way sent shivers up and down my spine. Yes, there was in fact a conspiracy to suppress the science behind the link between smoking and cancer. She described the anatomy of this conspiracy in minute detail, well researched and referenced. The continued legacy of the tobacco strategy is our callousness toward the bulk of chemicals on the market and their health effects, our allegiance leaning more towards saving the economy than lives.
In her new book, which I have not yet read, Davis turns her quill to the cell phone and electronics industry. If this book is as well researched and footnoted and damning as the Cancer book, we should all pay attention. Of course, I can see how the message can become quite unpopular -- the devices that we all rely on, even are addicted to, the devices that make the world go round and add trillions of dollars to our beloved economy, are on trial! Radiation from cell phones, brain cell death and proliferation, especially in children -- not a comfortable line of logic to follow. Yet, if we are to be balanced and scientific about it, should we not examine the science that this author presents, rather than knee-jerk into the ad hominem?
Now, I am singling out this particular tweet unfairly -- the person who wrote it probably did not give much thought to the words. But this is an influential individual, and, as I already mentioned, we often join an opinion bandwagon for reasons other than rational thought or preponderance of evidence, so one influential individual may blind the less critical masses to the very opinion nature of this remark. This is a potential broken telephone game, which will end up in "oh, her, she is a crank, a pseudoscientist and not credible". In fact, the only questions of her credibility that I could find was in comments from listeners like this:
So, why are we skeptical of her? I think we need to be very honest with ourselves here and really examine our objections. And I would go even further to say that we not only need to examine the science, but we need to be cognizant of whether we are examining this science with the same amount of ferocious scrutiny as we examine science that aligns with our preconceived notions of the world. For it is this magnitude of ferocity ("ferocity quotient"?) that will tell us whether we are biased or completely objective. Ultimately, the question each of us needs to answer for herself is this: Is it the science or is it the message?
Please, don't kill the messenger!
I'm skeptical of her; hearing same from many others: Ntl Acad of Sci researcher: "Disconnect: Truth Abt Cell Phone Rads http://bit.ly/dxpTtGNow, there is really nothing fundamentally wrong with this statement -- we seek out the opinions of those we trust and align ourselves with them in the absence of evidence to the contrary; this is how friendships and other relationships tend to work. But what is striking to me is the disparity of effort to seek out real evidence when it comes to stuff we agree with vs. stuff that we do not like.
The link is to a radio interview with Devra Davis, whom I have mentioned on several occasions on this blog. I read her book on cancer with great interest, and the history that she told in a measured and well documented way sent shivers up and down my spine. Yes, there was in fact a conspiracy to suppress the science behind the link between smoking and cancer. She described the anatomy of this conspiracy in minute detail, well researched and referenced. The continued legacy of the tobacco strategy is our callousness toward the bulk of chemicals on the market and their health effects, our allegiance leaning more towards saving the economy than lives.
In her new book, which I have not yet read, Davis turns her quill to the cell phone and electronics industry. If this book is as well researched and footnoted and damning as the Cancer book, we should all pay attention. Of course, I can see how the message can become quite unpopular -- the devices that we all rely on, even are addicted to, the devices that make the world go round and add trillions of dollars to our beloved economy, are on trial! Radiation from cell phones, brain cell death and proliferation, especially in children -- not a comfortable line of logic to follow. Yet, if we are to be balanced and scientific about it, should we not examine the science that this author presents, rather than knee-jerk into the ad hominem?
Now, I am singling out this particular tweet unfairly -- the person who wrote it probably did not give much thought to the words. But this is an influential individual, and, as I already mentioned, we often join an opinion bandwagon for reasons other than rational thought or preponderance of evidence, so one influential individual may blind the less critical masses to the very opinion nature of this remark. This is a potential broken telephone game, which will end up in "oh, her, she is a crank, a pseudoscientist and not credible". In fact, the only questions of her credibility that I could find was in comments from listeners like this:
I'm really disappointed that Leonard didn't ask this woman any tough questions, and pretty much just let her rant using his show as her soapbox. I just looked up her CV, and this woman does not have one degree in science. Her background is in sociology and history. Where's the science?Well, if one bothers really to look up her credentials, this is what we find:
Dr. Davis holds a B.S. in physiological psychology and a M.A. in sociology from the University of Pittsburgh, 1967. She completed a Ph.D. in science studies at the University of Chicago as a Danforth Foundation Graduate Fellow, 1972 and a M.P.H. in epidemiology at the Johns Hopkins University as a Senior National Cancer Institute Post-Doctoral Fellow, 1982. She has also authored more than 190 publications in books and journals ranging from the Lancet and Journal of the American Medical Association to Scientific American and the New York Times and blogs in Freakonomics for the New York Times, Huffington Post and elsewhere.And her honors and appointments span the entire page. So, in terms of pedigree, she is impeccable, she has authored more respectable peer-reviewed publications than many giants I know, and she has been on all the "right" commissions and boards.
So, why are we skeptical of her? I think we need to be very honest with ourselves here and really examine our objections. And I would go even further to say that we not only need to examine the science, but we need to be cognizant of whether we are examining this science with the same amount of ferocious scrutiny as we examine science that aligns with our preconceived notions of the world. For it is this magnitude of ferocity ("ferocity quotient"?) that will tell us whether we are biased or completely objective. Ultimately, the question each of us needs to answer for herself is this: Is it the science or is it the message?
Please, don't kill the messenger!
Thursday, November 11, 2010
More thoughts on lung cancer screening
Today I want to continue in the vein of yesterday's post and discuss a slightly different aspect of the NLST study. But first, a story. I was at a meeting a couple of weeks ago, where we were discussing antibiotics in pneumonia. We were talking about mortality, and one of the docs said something that became a constant mosquito buzz in my brain, which I have been unable to swat away. He said that antibiotics never claimed to reduce all-cause mortality, only mortality associated with infection. Now, on the face of it, the statement makes perfect sense, particularly as you think mechanistically. But it also makes an important point from the perspective of population epidemiology. And it just happens to be related to the NLST study.
Yesterday we talked about the characteristics of the screening tests and in what populations it may make sense. But all of these current and future decisions rest on the results for the primary outcome, which was mortality from lung cancer, reaching an impressive 20% relative reduction. But what about all-cause mortality, and why should we care? Well, saving people from cancer deaths is great, and this is what early screening can mechanistically do. But it is only great if they are not at risk of dying of something else and can derive a meaningful benefit from a life not terminated by an undetected cancer. Unfortunately, as you well know, life does not work this way, and there are many other reasons that people die -- old age, cardiovascular disease, and the like. In epidemiology we call these "competing risks", and it is these risks that sometimes dilute the excitement over the effectiveness of our interventions to a Pyrrhic victory.
Let us apply this to the NLST, or at least what we know today. The results reported are so cursory at this time, that we have to make a lot of educated guesses. But when has that ever stopped us? The report, among other data, states "all-cause mortality was 7% lower" in the CT than in the CXR screening group. The report fails to say whether this is a relative or an absolute reduction, and, as you know, this is a critical distinction. It is critical because, if my calculations are correct, the 20% relative reduction in the cancer mortality detected represents only a 0.3% absolute reduction in deaths from cancer. Given a couple of other tid-bits peppering the report, a few numbers can be back-calculated:
So, again, if my calculations are correct, the all-cause mortality is ~6.4% in the CXR group and ~5.5% in the CT group, so no way can there be an absolute 7% reduction in mortality, and the absolute reduction then turns out to be 0.9% over the 5-year follow-up. And here is what it looks like graphically:
There actually is a reduction in non-cancer deaths in the CT arm. Why this is remains unclear so far, but may well be due to the observation bias, as the study was not blinded. If this is the case, the differences should smooth out over further follow-up period.
But here is my bottom line. Since we live in the world of competing risks, the question becomes "What is the value of screening with CT scans to prevent 0.3% of cancer-related deaths over 5 years?" And how much of this 0.3% benefit is due to lead time bias? This question cannot be answered yet, as we do not have the accounting of either the adverse events related to screening and follow-up, or of the financial costs, or of the patient utilities for either strategy. What we can guess is that the risks have to be miniscule in order not to overwhelm the very small benefit detected, even if it is real.
I am personally not that happy that this report was released the way it was -- no mention of absolute risk reductions, no explicit disclosure of the denominators, no hint as to what the comparative risks of the strategies are (both long- and short-term), and most importantly what implications either strategy has for the patients' quality of life. I guess all of these questions will be answered in the peer-reviewed publications that will result from this study. Fully and transparently. Without any politics or obfuscation. I am waiting with baited breath.
Yesterday we talked about the characteristics of the screening tests and in what populations it may make sense. But all of these current and future decisions rest on the results for the primary outcome, which was mortality from lung cancer, reaching an impressive 20% relative reduction. But what about all-cause mortality, and why should we care? Well, saving people from cancer deaths is great, and this is what early screening can mechanistically do. But it is only great if they are not at risk of dying of something else and can derive a meaningful benefit from a life not terminated by an undetected cancer. Unfortunately, as you well know, life does not work this way, and there are many other reasons that people die -- old age, cardiovascular disease, and the like. In epidemiology we call these "competing risks", and it is these risks that sometimes dilute the excitement over the effectiveness of our interventions to a Pyrrhic victory.
Let us apply this to the NLST, or at least what we know today. The results reported are so cursory at this time, that we have to make a lot of educated guesses. But when has that ever stopped us? The report, among other data, states "all-cause mortality was 7% lower" in the CT than in the CXR screening group. The report fails to say whether this is a relative or an absolute reduction, and, as you know, this is a critical distinction. It is critical because, if my calculations are correct, the 20% relative reduction in the cancer mortality detected represents only a 0.3% absolute reduction in deaths from cancer. Given a couple of other tid-bits peppering the report, a few numbers can be back-calculated:
So, again, if my calculations are correct, the all-cause mortality is ~6.4% in the CXR group and ~5.5% in the CT group, so no way can there be an absolute 7% reduction in mortality, and the absolute reduction then turns out to be 0.9% over the 5-year follow-up. And here is what it looks like graphically:
There actually is a reduction in non-cancer deaths in the CT arm. Why this is remains unclear so far, but may well be due to the observation bias, as the study was not blinded. If this is the case, the differences should smooth out over further follow-up period.
But here is my bottom line. Since we live in the world of competing risks, the question becomes "What is the value of screening with CT scans to prevent 0.3% of cancer-related deaths over 5 years?" And how much of this 0.3% benefit is due to lead time bias? This question cannot be answered yet, as we do not have the accounting of either the adverse events related to screening and follow-up, or of the financial costs, or of the patient utilities for either strategy. What we can guess is that the risks have to be miniscule in order not to overwhelm the very small benefit detected, even if it is real.
I am personally not that happy that this report was released the way it was -- no mention of absolute risk reductions, no explicit disclosure of the denominators, no hint as to what the comparative risks of the strategies are (both long- and short-term), and most importantly what implications either strategy has for the patients' quality of life. I guess all of these questions will be answered in the peer-reviewed publications that will result from this study. Fully and transparently. Without any politics or obfuscation. I am waiting with baited breath.
Wednesday, November 10, 2010
CT screening for lung CA: an epidemiology primer
Amid the hype surrounding it, there is an opportunity to ponder the new NCI CT screening study that reduced lung CA deaths by 20% over the 5-year follow-up. The study itself was interesting, as it was a randomized controlled trial of the screening. This means that, although the possibility of lead time bias remains as the explanation for some of the detected difference (this refers to the fact that in the CT scan group the cancers were diagnosed earlier and therefore the deaths may still occur but simply beyond the five-year follow-up period), this is less likely than in any other design. So, the findings, while intriguing, need to be considered with the modicum of caution as recommended by the NCI, particularly given the high number needed to screen to save one life (300), and the high number of false positives requiring invasive testing. Not to mention all the radiation exposure.
So, while the analyses of the trial continue, some groups, such as the Steelworkers' Union, have already jumped on the side of demanding screening for their members. Is this altogether unreasonable and premature? Well, while it may be premature, I do not think that it is altogether unreasonable. And this has to do with screening test characteristics, some of which are immutable and others exquisitely dependent on the population being screened.
The test characteristics that tell us how well a test detects disease are sensitivity, specificity, predictive positive value and predictive negative value. Sensitivity refers to how well the test picks up the disease that is really there, while specificity tells us whether we can trust that a positive test signifies the presence of the particular disease in question. We also calculate a positive predictive value (PPV, or how much we can trust that a positive test really signifies the presence of the disease), and a negative predictive value (NPV, or how sure are we that a negative test result really means the absence of the disease).
In epidemiology, where we are always concerned with denominators, we like to construct so-called 2x2 tables to illustrate. Here is an example:
The values in the squares signify the following: A = true positives, B = false positives, C = false negatives, D = true negatives.
And while both sensitivity and specificity of a test are intrinsic characteristics of the test itself and are not subject to change by the population risk of the disease, not so for PPV and NPV. These measures are sensitive to the pre-test probability of the disease being present. That is, the PPV and NPV of a test are enhanced if the population is enriched for persons with a higher likelihood of the disease.
This brings me to the Steelworkers' Union demand for CT screening. Here is their rationale:
So, while we are awaiting further data from the trial, the Steelworkers' Union may be on to something.
So, while the analyses of the trial continue, some groups, such as the Steelworkers' Union, have already jumped on the side of demanding screening for their members. Is this altogether unreasonable and premature? Well, while it may be premature, I do not think that it is altogether unreasonable. And this has to do with screening test characteristics, some of which are immutable and others exquisitely dependent on the population being screened.
The test characteristics that tell us how well a test detects disease are sensitivity, specificity, predictive positive value and predictive negative value. Sensitivity refers to how well the test picks up the disease that is really there, while specificity tells us whether we can trust that a positive test signifies the presence of the particular disease in question. We also calculate a positive predictive value (PPV, or how much we can trust that a positive test really signifies the presence of the disease), and a negative predictive value (NPV, or how sure are we that a negative test result really means the absence of the disease).
In epidemiology, where we are always concerned with denominators, we like to construct so-called 2x2 tables to illustrate. Here is an example:
The values in the squares signify the following: A = true positives, B = false positives, C = false negatives, D = true negatives.
And while both sensitivity and specificity of a test are intrinsic characteristics of the test itself and are not subject to change by the population risk of the disease, not so for PPV and NPV. These measures are sensitive to the pre-test probability of the disease being present. That is, the PPV and NPV of a test are enhanced if the population is enriched for persons with a higher likelihood of the disease.
This brings me to the Steelworkers' Union demand for CT screening. Here is their rationale:
"Millions of workers have been exposed to asbestos, silica, chromium, arsenic, beryllium, cadmium, nickel and combustion products — and all of these exposures are firmly established as causes of human lung cancer.
Union health and safety leaders and others need to meet in the very near future in Washington DC to devise a strategy for assuring that high risk workers are among the first to obtain the benefits of this new screening method."And here is why it is not altogether unreasonable. Now, it is well appreciated that these workers have high rates of smoking. According to the CDC, smoking alone increases the risk of lung cancer 10-20-fold. It is also well appreciated that occupational exposure to asbestos, for example, is associated with an enormous increase in the risk of lung cancer. More importantly, however, together with smoking these exposures gang up as a team to help each other to promote cancer much more effectively than if each were working alone. This is called potentiation, and it results in a multiplicative increase in lung cancer risk when both smoking and occupational exposure exist. Therefore, the population represented by the Steelworkers' Union is indeed enriched for the risk of lung cancer development, and may indeed be the population where both the PPV and the NPV are enhanced beyond what we see in smokers only. This means a higher degree of certainty that a positive CT finding truly represents cancer, as well as increased comfort that a negative test is not simply missing a cancer that is there. As a corollary, this means a potentially optimized risk-benefit balance for this screening test.
So, while we are awaiting further data from the trial, the Steelworkers' Union may be on to something.
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