Longevity, life expectancy, premature mortality: Are they lions and tigers and bears?

Before I set up the context for this post, I am going to throw this out to you. Think of putting rocks on a scale to achieve the weight of, let's say, 1,000 lb. And let's say that you are required to use rocks of similar size. You have a bunch of bricks -- these are your biggest "rocks," and you have a bunch of pebbles like the ones I have in my driveway (perhaps you have them in yours too). In order to get to 1,000 lb, will you need more bricks or more pebbles? I am not trying to trick you. This is just an illustration of the fact that you can get to the same magnitude of a variable (in this case weight) by either using a smaller number of more weighty components (bricks) or a larger number of lighter ones (pebbles). Keep this in mind as you read on below.

I got an interesting comment from Brad F. on my post from yesterday regarding the 10% number for the premature death avoidance attributed to access to medical care. He pointed me to a blog post on the always-informative The Incidental Economist web site which called this a "zombie statistic." Despite having a fifteen-year-old who is an avid fan of zombie fiction and film, I was not familiar with this term, but inferred its meaning pretty easily.

The gist was that when people started to look for the origins of this number, the evidence was difficult to find, and, when discovered, was at best shaky:

Thus, as Austin and Adrianna had found, the 35-year old CDC paper seems to be at the root of the often-cited 10% number; it’s “paper 0,” if you will. But those that continue to reference 10% as an estimate for health care’s contribution to health should know that the only evidence they are referencing is a survey of 40 people, done when Jimmy Carter was president. It’s not evidence-based except by the weakest notions of “evidence.” It’s really a zombie statistic.

My obvious next question was whether a more trustworthy estimate existed for the medical care's contribution to life extension in the US. In my search for a better estimate, I continued to go down the rabbit hole of links, arriving here, the AcademyHealth Blog, landing on the article called "Half of longevity gains due to health care." It was a summary of the attempt by the authors of The Incidental Economist to answer this very question. And what did they find? First, they quoted a NEJM citation from 2006, where it was claimed that 90% of the increases in life expectancy since the 1960s was due to reduction in cardiovascular and neonatal deaths. After meandering through several other sources, the authors concluded that we can attribute about 50% of the responsibility for extending our life to medical interventions.

And that's when I really confused myself. I started thinking about whether premature death and longevity are related, and how they may be related, and are we even talking about the same thing when we invoke each of them.

Premature mortality can be quantified in several ways -- 1). percentage of all deaths that are considered premature, or 2). proportion of people in a population whose death is considered premature (that would be so many cases per 100,000 population). Longevity, on the other hand, is a measure of the average life span of a population. The current life expectancy in the US is 78.8 years. This begs the question of how these two, premature deaths and life expectancy, are numerically related to each other. And can the latter go up without the former going down?

Well, if the language here is consistent with how we speak it, "premature" implies that we know what "timely" means. The definition of a "timely" death must be based on the average life expectancy in a population. This number varies according to certain characteristics of a population, of course, so different subgroups would have a different life expectancy. For example, at any given age, the life expectancy of a person with heart disease should be lower than that for a person who is perfectly healthy. If we can reduce the risk of a premature death in people with heart disease, their life expectancy should edge closer to that of a healthy individual. And, in fact, according to the literature, this has happened in cardiovascular patients, partly due to better treatment of blood pressure, and partly due to fewer people smoking and other healthful lifestyle modifications.

So, it's clear that when death due to a disease is postponed, longevity increases and, ergo, premature deaths drop. It's a bit circular, I know. But here is one interesting detail to consider. Longevity or life expectancy (I use them interchangeably) is an age average. So here is one question: Does the impact on the magnitude of life expectancy gains vary with the age of the population in which premature deaths are avoided? I know, its a clunky question. What I mean is, would you expect life expectancy to go up more, less or same amount if we manage to reduce premature deaths in infancy versus old age? If you consider that life expectancy is an average, then infant mortality attenuates this average severely (think adding a whole bunch of numbers into the denominator without contributing anything to the numerator). So you can imagine, if infant mortality goes down a lot (a big reduction in premature deaths), overall population life expectancy spikes decisively. Reducing premature deaths among the elderly, clearly, by this same calculation, will not result in nearly the same increase in life expectancy.

Another way of looking at this is to consider that a much larger reduction in premature deaths among the elderly (think driveway pebbles) than among infants (those sizable bricks) would be needed in order to reach a similar degree of longevity improvement. A less intuitive corollary of this is that we indeed can have an increase in premature mortality in a group that contributes little to longevity (the elderly) and still witness a large bump in life expectancy with a much smaller reduction in premature deaths within a group with an outsized contribution to longevity (infants). So that answers the second question I posed about these measures -- they can diverge.

Now, on to the estimated contribution of medical care to either or both of these. We have, in fact, witnessed a dramatic reduction in infant mortality. I found this report from Health Resources and Services Administration that infant mortality has dropped from 55.7 per 1,000 live births in 1935 to 6.8 per 1,000 live births in 2007. And here is what the authors cite as reasons:

...dramatic declines in infant mortality rates over the long term were due to large declines in mortality from pneumonia and influenza, birth defects, prematurity and low birthweight, respiratory distress syndrome (RDS), sudden infant death syndrome (SIDS), and injuries. Improvements in living conditions, advances in neonatal medicine and infant heath care, reductions in smoking during pregnancy, and increased access to and use of prenatal care have been suggested as factors responsible for decreases in infant mortality over the past several decades...  

 

And here is an interesting detail: the pace of this drop was a dizzying 3.1% per year on average between 1935 and 2000. However, between 2000 and 2007, the rate went down only from 6.9 to 6.8 per 1,000 live births, a staggering deceleration in this steep decline. A further detail indicates that "much of the statistically significant decline [occurred] in the neonatal period." The implication of this is that the latest declines are due to technology use, most likely among the very premature infants upon delivery. This is the very definition of access to medical care, and falls completely outside of the domain of public health.

Just one more random thought. Reductions in infant and cardiovascular mortality, each a product of both medical and public health interventions, are one side of the life expectancy equation. The other, darker, side is the fact that in some groups and locations in the US, the overall longevity is waning. Much of this phenomenon can be attributed to poverty, environmental factors and poor health behaviors, or, in sum, a reflection of our dismal investment in public health. And, sure, there is a component of access here too. And what about this calculus: Between 1990 and 2010, mortality from cardiovascular disease dropped by about 150,000 per year. That would be an awesome contribution to increased longevity and reduced premature deaths, if it weren't offset by all the deaths (presumably premature) related to the healthcare system itself.

I know that none of this gets to the crux of the matter: What is a reliable estimate of what proportion of the increases in life expectancy can be attributed to access to medical care? But what it does make me appreciate is the complexity of each and every term, every definition, every estimate that we confront daily. This devil, as always, is in the details.


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In honor of my father

My relationship with my Dad was not the easiest: we were so alike that all of his flaws were magnified in my estimation and bugged me disproportionately. But it was not always this way. When I was a kid in Odessa, we were really close. He told me tall tales to get me to eat my dinner, he took me for walks, he told me stories about our city. He instilled his love of Odessa in me, a love which I had forgotten until just the last couple of weeks.

I finally went back to Odessa after a 35-year absence. Just thirteen when we left, I was a reluctant party to our emigration. Despite my resistance, once we came to the US, I assimilated most successfully and repressed every notion of being from Odessa -- accent, uniquely Odessit attitude toward life, everything. Until I went back 10 days ago.

I arrived on a plane from Istanbul on Wednesday morning. The airport is a tiny one-story building with an attached airfield. Its only concession to modernity is buses that cart passengers between the building and the aircrafts. Stepping out of the plane, I sensed something achingly familiar in the light, the smells and sounds of the city. And this sense was to persist through the three days that I spent there.

Odessa, known as the "Pearl of the Black Sea", is the ultimate planned city. Established by the order of Catherine the Great in 1794, its role was to be a door to the southern trade routes, leading easily to the Ottoman Empire, as well as the ports of Western Europe. The architecture of the city, its art and literature, reflect the liberal, permissive attitude fostered by its founding planners that made it a civic and commercial success prior to the October Revolution of 1917. Now, emerging from her 70-year repression, Odessa greeted me with open arms.

The love for the city I learned from my father permeates everything in Odessa: Odessits love their city, despite her myriad flaws and imperfections. In this they are not given to extremes of thinking her either perfect or abominable. Their attitude is one of reverence and understanding. Some of her streets are perfect, while others are at the edge of ruin, and she still smiles and winks to us knowing that she transcends these minor details.

I went to the most treasured of places in Odessa, the Opera Theater. I sat in the sixth row, close enough to smell the make up. It was Rigoletto, and as Gilda was singing her aria, I could feel my Dad next to me, nodding and humming along with the music, as he always used to do. And I finally understood his years of silent longing for this most unpretentiously beautiful of all cities I have ever been to. Because if you ever visit Odessa, it will happen to you too.

So, on this, my first Father's day without you, I give you my love for our beautiful city.

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.

Requiem for my father

My father passed away about two weeks ago after battling a brain tumor for some time. Initially diagnosed with an extensive inoperable mass one and one-half years ago, upon presenting with a focal seizure, he did well with only one medication for seizure control for about ten months. Around Christmas of 2009, however, he landed in the hospital in status epilepticus that took three days to control. After these days of florid hallucinations alternating with pharmacologically achieved stupor, he came out of it remarkably cognitively intact, still able to quote poetry and sing Italian opera arias in their entirety. Although he was now unable to use his legs, he eagerly accepted the prospect of getting back on his feet by working hard in physical therapy. And though this never came to be, he managed to survive for additional seven months.

But my Dad was not your average guy. A survivor of World War II, an immigrant from the Soviet Union, a retired professor of mechanical engineering, he was at once a brilliant and an infuriating man. His stubbornness knew no bounds, and, even though he did not have the affinity for competitive sports, his drive to win was strong. He was a survivor by his nature and by his experience. So, when he was faced with the choice of a rapid decline and death versus some form of treatment for his tumor, he opted for the latter. As he and my mother put it, "doing nothing was not an option". So, when offered 6 weeks of radiation (5 days/week, with the risk of cognitive decline, the prospect of which terrified him as much as dying) together with oral and intravenous chemotherapy, he bravely accepted all.

As the days and the weeks of his treatment wore on, he would give me regular updates on how many radiation sessions he had completed and how many were still left to go. He suffered side effects with minimal complaining and never lost hope that the treatment would help him achieve a measure of meaningful recovery. This was not to be.

While I accompanied my parents to many of his appointments, I did not go to them all. And for this reason, I cannot say for sure what was said in some of them, and how different the content might have been from what they actually heard. But I did make the point of talking to every one of the specialists on the phone after they saw my father. They were all appropriately measured in their enthusiasm and recommendations while talking with me. But did they have the same demeanor with my family? Did my parents, both highly educated but neither medically savvy, take their enthusiasm for palliation as a promise of a cure? More importantly, are similar offers to try to prolong life by well-meaning and compassionate physicians to their desperate patients routinely misinterpreted on a grand scale by thousands as promises of cure? Is it possible that most people accepting the wonders of Avastin and other high tech interventions do not really internalize the reality that this and similar wonder drugs may give them merely two months of additional life? And further, do they think that these added months will be "normal" life?

Well, in my father's case, he got superb care at every institution he went to. His doctors and nurses were knowledgeable, compassionate, humane; in other words they were everything that healthcare professionals should be. Yet their eagerness to help a desperate and scared man may have inadvertently registered as false hope for results that were unlikely. My father tolerated his treatments, but over time began to exhibit cognitive decline, at first subtle, then more pronounced and made exquisitely more painful by his over-achiever baseline. He eventually succumbed to aspiration pneumonia after we made the painful decision to provide him with comfort care only.

After seven months of this most intense good bye, my mother now understands end-of-life issues better than many healthcare professionals. She is a seasoned and experienced decision-maker in a grave situation. But this experience comes at a steep price and a little too late, since I hope she is never faced with having to apply it again to a highly personal situation. She will not regret any of the choices that she and my Dad made in this journey -- they were all correct for them. But I have once again to question the wisdom and utility of making available treatments that make a difference at the slightest of the margins, that cost the society enormous resources and exact such high emotional costs from patients and their families.

Death is a natural conclusion to a life. Since we are not that good at "just sitting there", the vocabulary of "do nothing" needs to change to "helping patients die with dignity and comfort". The manipulative rhetoric of "death panels" has to be replaced with empathy and compassion. We are not above the laws of the Universe, we are not above the laws of physics and biology. We have to reposition our societal attitude toward death as an avoidable nuisance. And we have to ask: what are we prolonging in many of the cases that we treat at the end of life -- life or death? In his better days, my Dad might have asked an analogous question: are we living longer or does it just seem longer? And then he would have chuckled. Rest in peace, Dad.                        

Notes from a pandemic

Informative report in Eurosurveillance yesterday from New Zealand summarizing their H1N1 experience to date. A few encouraging signs are that a). the pandemic seems to be slowing down, b). proportion of people needing hospitalization is low, on the order of 0.3%, of whom ~12% require an ICU, and c). the case fatality rate is about 0.005%. All this in the face of an estimated attack rate of 11%. Very encouraging!

So, given what I said yesterday in my post, perhaps we can revise down our estimates for the US. If we were to do that on the back of a napkin, we would see a much less concerning picture of around 33 million infections, ~100,000 hospitalizations, ~12,000 ICU admissions and a little over 1,500 fatalities. Whew! Much better than what either our group or the White House advisers predicted. But is this the right time to recalculate? Maybe not.

Here is why. First, the Southern hemisphere is still in the middle of its flu season, and flu epidemics are known to come in multiple waves, separated by intervals from months to years. So, while the slow-down is encouraging, the fat lady has not yet sung. Second, the New Zealand report notes that the native Maori and Pacific peoples, two socio-economically disadvantaged ethnic groups with marked health disparities, exhibited triple to quintuple the attack and case fatality rates seen in their European counterparts. Given that 47 million people in the US are without routine access to the healthcare system, and racial and ethnic healthcare inequalities are rampant, we remain at high risk for seeing a lot of severe cases. Finally, and most importantly, New Zealand has a comprehensive nation-wide plan for mitigating a pandemic (and it is a much smaller nation than ours). Some of the phases include extensive pre-pandemic planning, improved surveillance, border control aimed at containment, and quarantining active cases if necessary. Our plan, which is actually many different plans, is still evolving and is unlikely to be this comprehensive, uniform or enforceable.

So, while I am encouraged by what is being reported, I am not willing to hang my hat on it yet, and neither should the US Department of Health and Human Services. It is true that we may get lucky this time. But this should serve as our national wake-up call, since in our global village it is only a matter of time until we are faced with a devastating health emergency. Do we really want to rely on luck next time?