Epidemiology of microangiopathy in Type 1 diabetes mellitus. A review

Diabetic nephropathy and diabetic retinopathy represent the two most important microangiopathic complications in Type 1 diabetic patients. Diabetes duration is the most important risk factor for both these complications. In the classic, juvenile-onset Type 1 (insulin-dependent) diabetic patient none of these complications will be present at diagnosis, and the earliest signs of complications will occur after 5-10 years of diabetes duration. For diabetic nephropathy, the incidence will thereafter increase dramatically, reaching a peak after 15-18 years of duration whereafter it declines. If the patient has not developed nephropathy after 30 years of diabetes duration, it is unlikely that he will ever develop the disease. With respect to retinopathy it is necessary to distinguish between simplex retinopathy (which continues to develop through out life) and proliferative retinopathy, which follows the same incidence pattern as nephropathy. This paper describes the epidemiology of these two microangiopathic complications. It focuses on the development of diabetic nephropathy, risk factors, preventive strategies and suggestions for treatment.