Occurrence and interrelationships of complications in insulin-dependent diabetes in Finland

Abstract

The purpose of the study was to examine the prevalence and interrelationships of micro- and macrovascular complications and their risk factors in insulin-dependent (type 1) diabetic patients. The prevalence of nephropathy, retinopathy and cardiovascular disease was examined, and their associations to risk factors (glycemic control, blood pressure, blood lipid concentrations) and neuropathy were estimated in a cross-sectional study. A total of 140 type 1 diabetic patients were examined. They were grouped by gender, age, and duration of diabetes into 14 subgroups of 10 patients each. Nephropathy was observed in 40%, retinopathy in 55%, and signs of cardiovascular disease in less than 5% of patients. Microvascular complications were associated with the duration of diabetes, systolic blood pressure, and serum triglyceride concentration. The glycosylated hemoglobin (HbA_1c) level was significantly associated with the presence of nephropathy, whereas the association with retinopathy was of borderline significance. Statistically speaking, the duration of diabetes, mean systolic blood pressure, HbA_1c, and triglyceride level explained 31% of the variation in log albumin excretion rate (P<0.001). Duration, age, and triglyceride level explained 46% of the variation in the severity of retinopathy (P<0.001) and 31% of the variation in the vibration perception threshold in the ankle (P<0.001). While the well-established risk factors (duration of diabetes, hyperglycemia, and hypertension) are associated with microvascular complications, more than half of the variation in their severity cannot be explained. An additional risk factor may involve triglycerides even at a normal serum concentration. The mechanism could be the incorporation of triglycerides in the cell membrane, leading to variations in membrane fluidity.