Decreasing Incidence of Severe Diabetic Microangiopathy in Type 1 Diabetes

Decreasing Incidence of Severe Diabetic Microangiopathy in Type 1 Diabetes Peter Hovind , MD 1 , Lise Tarnow , DMSC, MD 1 , Kasper Rossing , MD 1 , Peter Rossing , DMSC, MD 1 , Stefanie Eising , MD 1 , Nicolai Larsen , MD, PHD 1 , Christian Binder , DMSC, MD 1 and Hans-Henrik Parving , DMSC, MD 1 2 1 Steno Diabetes Center, Gentofte, Denmark 2 Faculty of Health Science, University of Aarhus, Aarhus, Denmark Abstract OBJECTIVE —Conflicting evidence of a decline in incidence of microvascular complications in type 1 diabetes during the last decades has been reported. To assess recent trends in the cumulative incidence of diabetic microangiopathy in type 1 diabetes, we analyzed data from long-term prospective observational studies lasting ≥20 years. RESEARCH DESIGN AND METHODS —A total of 600 Caucasian patients with onset of type 1 diabetes between 1965 and 1984 were followed until death or until the year 2000. Patients were divided into four groups based on the year of diabetes onset: group A, 1965–1969 ( n = 113); group B, 1970–1974 ( n = 130); group C, 1975–1979 ( n = 113); and group D, 1979–1984 ( n = 244). Group A, B, and C are prevalence cohorts identified in 1984; group D is an inception cohort. RESULTS —In patients followed for ≥20 years, the cumulative incidence (95% CI) of diabetic nephropathy after 20 years of diabetes (urinary albumin excretion >300 mg/24 h) was reduced in patients with more recent diabetes onset (groups A–D): 31.1% (22.5–39.7) vs. 28.4% (19.8–37.0) vs. 18.9% (10.9–26.9) vs. 13.7% (6.2–21.2) ( P = 0.015). Similarly, the cumulative incidence of proliferative retinopathy was as follows: 31.2% (22.2–39.8) vs. 30.3% (22.2–38.4) vs. 19.3% (11.2–27.4) vs. 12.5% (5.2–19.8) ( P < 0.01). In the latter groups, antihypertensive treatment was started earlier, blood pressure and HbA 1c were lower, and fewer patients smoked. CONCLUSIONS —Our study demonstrates a decrease in the cumulative incidence of diabetic microangiopathy in type 1 diabetes over the past 35 years. Improved glycemic control, lower blood pressure (in part due to early aggressive antihypertensive treatment), and reduced prevalence of smoking rates were associated with the improved prognosis. HPLC, high-performance liquid chromatography UAE, urinary albumin excretion Footnotes Address correspondence and reprint requests to Peter Hovind, MD, Steno Diabetes Center, Niels Steensens Vej 2, DK-2820 Gentofte, Denmark. E-mail: phovind{at}dadlnet.dk . Received for publication 28 October