Incidence and risk factors for stroke in type 2 diabetic patients: The DAI study

BACKGROUND AND PURPOSE: Type 2 diabetes mellitus is a strong predictor of cerebrovascular disease, yet few studies have assessed the incidence of stroke and the role of other risk factors in unselected type 2 diabetes mellitus populations. METHODS: We prospectively followed-up 14,432 type 2 diabetes mellitus patients, aged 40 to 97 years, with and without a history of cardiovascular disease at enrollment, and we estimated the incidence of stroke and the hazards ratios with respect to clinical variables. RESULTS: During a 4-year follow-up, 296 incident stroke events were recorded. In persons with no history of cardiovascular disease, the age-standardized incidence of stroke (per 1000 person-years) was 5.5 (95% confidence interval, 4.2 to 6.8) in men and 6.3 (95% confidence interval, 4.5 to 8.2) in women. In persons with a history of cardiovascular disease, it was 13.7 (95% confidence interval, 7.5 to 19.8) in men and 10.8 (95% confidence interval, 7.3 to 14.4) in women. The hazards ratios of stroke incidence varied according to age, sex, and history of cardiovascular disease. Among men with no history, HbA1c and smoking were predictors of stroke. Among patients with a history, the risk factors were, in men, therapy with insulin plus oral agents, treated high total cholesterol and low HDL cholesterol, whereas in women microvascular complications were a risk factor. Previous stroke was a strong predictor of stroke in both sexes. CONCLUSIONS: Age and previous stroke are the main predictors of stroke in diabetes. The combined role of Hba1c, microvascular complications, low HDL cholesterol, and treatment with insulin plus oral agents highlights the importance of diabetic history and clinical background in the development of stroke.