Ronald Ricker posted today about upcoming physician shortages and our failure to deal with them. In his writing he considers a number of improvements in health that have increased our lifespans substantially over the past 150 years. His key message, that we are not training enough physicians, is good. I disagree strongly with one of his assertions:
The discovery of insulin by Banting, Best, et. al. largely wiped out the scourge of diabetes.
Before Banting's work, what we now call type 1 diabetes mellitus produced a rapid death by starvation. Some patients could hang on for months on a diet of fat and protein, but without insulin replacement the Reaper came knocking before too long. Insulin allowed these patients to metabolize carbohydrates and survive. In 1921, it seemed the scourge of type 1 diabetes had been wiped out.
Of course, most patients with diabetes mellitus have always had the less dramatic, insidious type 2. This form usually occurs in older individuals, often in association with obesity and insulin resistance. Kimmelstiel and Wilson published the first description of the pathology of diabetic kidney disease in 1936 (PDF here). The discovery of insulin allowed those with type 1 diabetes to live long enough to develop this condition, as well as other complications of the hyperglycemic state. Today, despite improvements in glycemic control, approximately 40% of patients with diabetes of any type will develop kidney complications. Diabetes has become the leading cause of permanent kidney failure in the US, producing 154 new cases per million population per year. Nearly 1,800 people out of every million in the US have permanent kidney failure; of these, over 1/3 suffered this fate from diabetes (see figure from US Renal Data Service).
Insulin seemed miraculous to the children and young adults who developed type 1 disease; however, its discovery did not cure this condition, nor did it "wipe out the scourge." Instead an acute fatal illness became a chronic disease, much like the type 2 form. We ended up with more people living with diabetes.
We still need more research on diabetes and its complications. Better metabolic control, via an artificial pancreas or islet transplants, could potentially cure type 1 diabetes. Type 2 disease, where the initial issue is usually insulin resistance, will not be cured through these endeavors. We need to understand more about how the complications of diabetes, including kidney failure, blindness, nerve damage, gastrointestinal dysfunction, and cardiovascular disease, develop and progress. Why do only 40% of patients get kidney damage from diabetes? What makes one person vulnerable while another patient remains protected?
It has been more than 3 decades since microalbuminuria, the first clinical marker of diabetic kidney disease was reported. Over that time, we have discovered important flaws in its specificity and sensitivity - so we really don't have a marker of early kidney disease! We have not developed an effective new treatment in more than 20 years. I would say we are overdue.
Recent reports in the Journal of the American Society of Nephrology suggest that circulating receptors for TNF alpha may provide a more useful biomarker of risk. It would be a big step forward for research (and patient care in the future), but it is not enough. Unfortunately, recent hits to the NIH budget mean fewer physicians and scientists will be studying these diseases (and a multitude of others).
In short, insulin saved lives, but the scourge of diabetes is still going strong.