Where is the Epidemiological Evidence?

I spent the first twenty years of type 1 diabetes before the invention of home glucose meters. During this period, only urine sugar tests were available to give a rough indication of blood sugar values, but these bore little or no relation to current levels, since they showed less sugar if the patient drank more, varied with the changing renal threshold for dumping excess sugar from the blood into the urine, and represented the total sugar accumulation since the last urination hours before the test. The only ‘management’ of diabetes was to stick to a sugar-restricted diet and reduce or increase the once-a-day insulin dose by 25% if the previous day’s urine sugars had been low or high. Insulin was supposed to be taken only once a day, regardless of how high the urine sugar was.

When I would go to the Joslin’s Clinic once every few years for an actual blood sugar test, the result would always be around 240. I expressed concern about this to one of the doctors, who assured me that this was nothing to worry about, since the average was around 270 in the patients tested there. It makes me smile now to see how patients panic if they get a single reading above 200, since I survived a whole generation with few results lower than that.

But while you would expect that the clinical complications in type 1 diabetics would be vastly better today than they were then, this expected degree of improvement has not materialized. Prior to 1950, 50% of diabetics developed renal failure, and while that is lower than today at 30%, that is not such a huge drop as you would expect from all the effort now put into blood sugar control. Microalbuminuria, a condition often leading to diabetic renal failure, has remained identical from 1986 — when patients had only just started using home meters, to 1996, after a decade of home meter use. A large-scale study of diabetic kidney disease in 1941 found the condition only in patients over 40 years of age, but now it is found to occur in many patients under 30. There was also no decline in childhood deaths from diabetes from 1984 to 1998.
Epidemiologically, there should have been more visible progress by now, more than 20 years after ‘strict control’ became possible, and this raises interesting theoretical questions about the nature of diabetic complications.

Sources: J. Ekoe, et al, ‘The Epidemiology of Diabetes Mellitus’ (London: John Wiley, 2001) p. 341; Elliot Joslin, et al, ‘Joslin’s Diabetes Mellitus’ (Philadelphia: Lippincott, 2004) p. 798; J. Cameron, "The Discovery of Diabetic Nephropathy," Journal of Nephropathy, 19, Supplement 10: 575 (2006); J. DiLiberti and R. Lorenz, "Long-Term Trends in Childhood Diabetic Mortality," Diabetes Care, vol. 24, no. 8, p. 1348 (2001); R. Amin, et al, "Unchanged Incidence of Microalbuminuria," Archives of Diseases of Childhood, vol. 94, no. 4, p. 251 (2009)