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Tuesday, September 10, 2013

What is "overdiagnosis"?

I got an invitation in my e-mail a couple of days ago for a dinner presentation to the Central Oregon Medical Society given by H. Gilbert Welch M.D. on the subject of overdiagnosis. I was intrigued. A little less than a year ago Dr. Welch, an internist and professor at Dartmouth Medical School and Archie Bleyer M.D., a former pediatric oncologist and now a research professor at Oregon Health and Sciences University wrote a controversial article presenting compelling evidence that regular mammograms lead to death and disability related to aggressive treatment in many of the patients who were diagnosed with breast cancer but that it did not significantly improve survival.

Dr. Welch has been studying overdiagnosis for a couple of decades and has written two books, Should I Be Tested For Cancer-maybe not and here's why and Overdiagnosed: making people sick in the pursuit of health. I have peeked at the second one and found it to be well written, with a non-physician audience intended.

Overdiagnosis is defined as detecting disease in patients without symptoms which, if undetected and untreated, would lead to no harm. This is not a good thing. People who find that they have a disease often use more resources, get more testing and treatment with associated costs and side effects, and feel worse about their health. In the small picture, this is caused by increasingly sensitive screening tests, more strict definitions of normal and increased use of imaging procedures which see things we weren't even looking for. It has been pretty well established for breast cancer screening and for thyroid imaging which detect low level cancers which probably would never progress and for prostate cancer for which, in most cases, the treatment is worse than the disease, and the disease is extremely common. It also appears to be true for kidney failure, which has been diagnosed more and more commonly in elderly people despite the fact that we know their kidney function normally declines with age. Overdiagnosis occurs when we remove colon polyps which had no malignant potential during excessively frequent colonoscopies and when we screen ancient and dying people for cancers which would never contribute to their inevitable demise.

Overdiagnosis is estimated to result in many many billions of dollars of excess healthcare spending.

In the big picture, overdiagnosis is caused by the economics of our medical system: defining more people as sick increases use of medical care which keeps doctors and staff and the many industries that serve us and our patients in business. The patients who are overdiagnosed are also not very sick, or not sick at all, so they are easier to treat, mostly. It's a win/win situation. Except that it isn't.

Reducing our thresholds for defining disease is not entirely a bad thing, though. We have gradually reduced the blood sugar at which we diagnose a patient with diabetes. It turns out that slightly elevated blood sugars are nearly as predictive of bad outcomes as higher blood sugars. It has been my experience, as well, that patients who are told they have diabetes often immediately take seriously their needs for lifestyle changes, so they begin eating more healthily, exercising and losing weight which is undeniably good for them.

September 10-12, 2013 is the first ever conference on overdiagnosis at Dartmouth University, in which there will be talks about the extent of the problem and then discussion of ways to roll back excesses. Already there has been a conference on Selling Sickness which involved activists of many descriptions who came up with some resolutions to reduce "disease mongering". These include improving research to determine what tests and treatments are actually effective and separating funding for this from parties whose economic interests would benefit from positive results. The American College of Physicians and many specialty organizations have gotten behind the "Choosing Wisely" campaign which targets tests, procedures and treatments which are without proven benefit, though they may be widely practiced.

When we, as doctors, think about it, we don't want to be doing things that are of no particular benefit to our patients, even if it does give us job security. It makes us feel that our jobs are meaningless and it puts us at odds with the people we treat. We have been expanding our scope this way for so long, though, that it takes awhile to change gears, and communication and education has to be excellent in order that we come to consensus. Many of us think we will be sued if somebody develops a condition that we could have screened for, even if that screening rationally would not have made a difference in their outcome. We need good solid support for curtailing our excesses.

Central Oregon is a long way away from where I am, a good 7 plus hour drive, and the talk is only a couple of hours long, so I think I'll just read his book and read the articles that come out of the Dartmouth conference. If doctors who are well respected put their energy into this effort, good will come of it. I'm proud of us for trying.

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