Risk factors for progression of microvascular complications in the Stockholm Diabetes Intervention Study (SDIS).

Ninety-six patients with insulin-dependent diabetes mellitus (IDDM), non-proliferative retinopathy, normal s-creatinine and previously high blood glucose levels were followed for 5 years. In multivariate analyses the mean HbA1c level (14 values during 6-60 months) was significantly correlated with albumin excretion level (P less than 0.01), retinopathy (P less than 0.001), motoric and sensoric nerve conduction velocities (P less than 0.01), thermal threshold on the foot (P less than 0.01), the respiratory sinus arrhythmia (P less than 0.01), the valsalva ratio (P less than 0.05) and the orthostatic blood pressure reaction (P = 0.05) after 5 years. Neuropathy was related to both the HbA1c value at baseline (P less than 0.05) and the mean HbA1c value during the study (P less than 0.001). Smoking habits were correlated with the total number of complications deteriorating (P less than 0.05), as was HbA1c during the study (P less than 0.001). Patients with an initial HbA1c of 9% or more could reduce the risks for deterioration of microvascular complications to 10-15% by reducing their HbA1c below this level.