Tuesday, February 8, 2011

Medical decision making: More signal less noise, please!

It's official, I'm a country bumpkin! Driving in Boston last week I was distracted, annoyed, made anxious and confused by the constant traffic, billboards and signs. Even highway markings confused me, particularly one indicating a detour to Storrow Drive East, which never materialized. Despite the fact that I know the geography of Boston like the back of my hand, I nearly went down the wrong streets multiple times, including driving the wrong way on some one-way roads. Yes, I am now the menace I used to save my prize driving language for in my younger days.

But it seems that over the years of my living away, there has been a sharp increase in the information thrown at me from all directions, accompanied by a decline in places to rest my gaze without suffering the perseveration of conscious processing. And while the value of this information is at best questionable, the sum total of this overstimulation is clearly confusion, wrong road choices and possibly a reduction in the safety of my driving. This whole experience reminded me of Thomas Goetz's distaste for how medical results are reported. If you have not seen him preach about it, you really should. Here is his excellent TED talk on the subject.

It is ironic that during this overwhelming city visit I also had the chance to speak to a doctor about "routine" preoperative testing and its value. Before surgery, it is recommended that a patient get a screening evaluation. Yet the components of this evaluation vary widely, and may include blood work, urinalysis, electrocardiogram, a chest X-ray and the like. Although evidence suggests that most of the points of this evaluation are useless at best, many institutions continue to order a shotgun panel of preoperative testing for everyone. This one-size-fit-all medicine results in reams of useless and distracting information, a high frequency of abnormal findings of questionable significance, a potential for harm, worry and needless healthcare spending. In my particular conversation I asked the anesthesiologist what the pre-test probability for someone with my characteristics was for a useful chest X-ray result, for example, and whether the fancy electronic medical record used by the hospital could help her determine this. While the answer to the former question was "probably exceedingly low", the answer to the latter was a definitive "no." So, given some elementary thinking, it became clear that a patient like me should not in fact be subjected to a chest X-ray, since any pathology found on one would likely represent a false positive finding, which would nevertheless require potentially invasive follow-up. And guess what? By focusing on the particular individual in the office, rather than all comers, we could have gone through the entire menu of the possible preoperative tests "routinely" ordered and eliminated most if not all of them. But my bet is that not all patients, not even all e-patients, either know or are able to initiate this type of a critical discussion. And yet what tests to obtain, if any, should always be a thoughtful and individualized decision. To approach testing in any other way is to risk generating noise, distraction and harm.

And this brings me back to Thomas Goetz's idea of redesigning how test results are reported. I love his idea. But to me what needs to happen before making the data patient-friendly, is making the decision-making provider-friendly. So, great idea, Mr. Goetz, but let us move it upstream, to the office, where the decision to get chest X-rays, cholesterols and urinalyses is made, and help the doctor visualize her patient's risk for a disease being present, the characteristics of the test about to be ordered, the probability of a positive test result, and all the downstream probabilities that stem from this testing, so as to put a positive test result in the context of the individual's risk for having the disease. Because getting the results of tests that perhaps should never have been obtained in the first place is following the GIGO principle. It is generating noise, distraction and detours going wrong way down one-way roads. And when applied to medicine, these are definitely unwelcome metaphors.

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