Map of life expectancy at birth from Global Education Project.

Tuesday, April 26, 2005

An ounce of prevention is worth . . .well, sometimes 8 grams

I don't talk much about what's in the medical journals because they're mostly subscription only and I can't give y'all links. (Were I to reveal the secret code, deep the doo doo would be.) But physicians are a new priesthood, it is not for ordinary people to know their secrets.

Iona Heath, writing in the British Medical Journal, cites (the great) Amartya Sen as pointing out that in Bihar, India's poorest state with the lowest life expectancy, rates of self-reported illness are lower than they are in the United States. "It seems that the more people are exposed to doctors and contemporary health care, the sicker they feel." Why? Because they've all been diagnosed with something (hypertension, hypercholesterolemia, etc.) and their expectations are much higher so that aches and pains and getting old are interpreted as abnormalities. Heath sees a massive misallocation of resources with essentially healthy rich people taking all sorts of pills while truly sick poor people don't take any.

The problem with this analysis is, of course, that if we stopped investing so much in preventive medicine in the rich countries, the resources would not be magically reallocated to Bihar and the Congo. What's going to determine what we rich folks do is what's in it for us. In the March 8 BJM Barratt and colleagues calculate that for every 1,000 women who get a screening mammogram over ten years, 167-251 (rising with age) get an abnormal result; 56-64 get at least one biopsy; and from 9-26 have an invasive cancer diagnosed. 3-6 have a so-called ductal carcinoma in situ diagnosed. That means abnormal cells confined to the milk duct, and it is unknown what percentage of them would ever go on to cause trouble. We don't know because we always remove them. However, cancer is also diagnosed in women who are not screened, albeit usually at a more advanced stage. Over 10 years, for each 1,000 women screened, there are .5 fewer cancer deaths for those age 40-50, and 2, 3 and 2 fewer deaths respectively for each successive ten-year age cohort. So if you have a mammogram, you have about a 20% chance of getting the shit scared out of you, a 6% chance of having to undergo a biopsy, a 2% chance of undergoing surgery and/or radiation or chemotherapy, and a .02 percent chance of extending your life.

You persons of maleness out there may have been urged to undergo prostate cancer screening. There is actually no evidence that prostate cancer screening will extend your life by one minute, but it could very well cause you to be diagnosed with prostate cancer (which it turns out, upon autopsy, that 70% of elderly men have when they die, without even knowing it and without it causing them the slightest problem), and the treatment (which, now that you've been told you have cancer, you will almost certainly get) may leave you incontinent of urine and unable to, you know, do it. And in the latter case, Viagra probably won't work.

Just something to think about.

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