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Friday, June 7, 2013

Learning from Diabetes

In a recent post, I wrote about how 126 became the cutoff for diabetes. It turns out that it was my fantasy about how 126 became the cutoff for diabetes. In response to the post, I got an email with a link to an article about the diagnosis of DM, which is, in the words of the person who sent it, "eerily like stuff going around re the DSM." I can't vouch for the accuracy of the article, but I'll summarize briefly.

A long time ago, back in the 70's, there were multiple standards for diagnosing diabetes. The reason for the multiple standards was that if you graph the sugars of a varied population at any given time, some will be elevated, but those don't necessarily correspond to the people who have diabetes.  Additionally, the graph never "jumps", so there's no clear cutoff point.

And at the time, there were limited treatments for diabetes, and essentially nothing to keep early type 2 from progressing. In addition, diabetes was quite stigmatized, and people with a diagnosis of DM could be refused health insurance, life insurance, employment, even a driver's license.

In 1978, the NIH convened a committee to establish a definition of diabetes, and the committee decided to place the cutoff higher than any standard had heretofore done, so that only people who unequivocally had DM would be given the diagnosis, and people who couldn't be helped anyway, such as early type 2 diabetics, would be spared the stigma, and its practical consequences.

And since a graph of a general population did not have a clear cut off point for DM, the committee looked at a subculture, the Pima Indians, whose graph did make a jump. Those Pima Indians whose Oral Glucose Tolerance Test was under 200 showed no symptoms of retinopathy, and those who did show signs of retinopathy had OGTT's over 240.

Then the committee decided to put the cutoff for fasting glucose at 140, higher than that of the typical diabetic Pima Indian, whose fasting glucose would hover around 120. Presumably this was done because at the time, OGTT was the test expected to be used to make a diagnosis, not fasting glucose.

In 1995, another committee was convened to re-examine the decision of the 1978 committee. This committee decided to use fasting glucose as the diagnostic test, presumably because it was cheaper, and it used a cutoff of 126, even though 121 seems to correspond with an OGTT of 200. They went with the highest number they could find in any study, specifically, a study of 13 Pacific populations.

There's more to the saga, but I'm gonna stop here with the diabetes. The take-home lesson for me is, Psychiatry is not such an outlier.

There are groups of people, including Gary Greenberg and his Book of Woe, who claim that Psychiatry is not as scientifically based as other medical specialties. Then there are other groups that claim it is scientific. Well, it appears to be at least as scientific as endocrinology.

A known disease entity, no one definitive diagnostic system, definition of disease determined by committee based on dubious scientific conclusions, the political stance not to further stigmatize people suffering from the disease, and a subsequent committee that examined the problems with the first committee's decisions, and then went on to make its own, new mistakes.

There is nothing new under the sun. A generation passes, and the world remains the same.

Read the article. It'll spook you. Even if it isn't accurate, it's exactly the same kind of rhetoric taking place now, about DSM-5.