Again thanks to the most recent issue of Primary Care Medical Abstracts, I learned of a study of screening for adult-onset (Type 2) diabetes that further stresses the position I have been arguing for here for a good while, that it’s basically a misunderstanding of the disease to imagine that the answer is better control of blood sugar. The study in question is by a group at Cambridge, UK headed by Rahman:
The question Dr. Rahman and colleagues set out to answer, using a large population cohort that they followed for 12 years, is how much earlier you learned somebody had diabetes if you did population screening for the disease, rather than waiting for symptoms to develop that led the individual physician to do the tests that led to the diagnosis. The authors concluded that you “gained” 3.3 years through population screening. As all these people (being Brits) had good access to care by their general practitioners, who were informed of screening results, the mantra that we all devoutly believe, that early diagnosis is always better, would lead you to expect that those whose diabetes was detected by early screening would do better than the comparison group who were diagnosed only through actual symptom development.
And you’d be wrong, as the study showed no differences in a large number of important complications of diabetes.
Dr. Rahman and colleagues conclude that there is at this time no good evidence for population screening of asymptomatic patients, which happens to be what the U.S. Preventive Services Task Force had already concluded based on other evidence. The point I want to draw is somewhat different. If our old model of diabetes as a disease of out-of-control blood sugar, which should be made better (and complications prevented) by tight control of blood sugar, were valid, then we’d expect screening to be effective in delaying the onset of complications. The fact that screening had no measureable effect is just one more bit of evidence that the old model is flawed.
If the old model is flawed, why does it remain so influential? Well, the old model sells drugs and devices (specifically, all the test strips for those nice glucose monitors that are so heavily advertised on TV). So long as so much money can be made from the incorrect model of diabetes, don’t expect that those who control the airwaves are likely to work to educate us on a better model.