Cardiovascular morbidity and mortality in type 2 diabetic patients: a 22-year historical cohort study in Dutch general practice

Abstract

A historical cohort study was performed to assess cardiovascular morbidity and mortality in Type 2 (non-insulin-dependent) diabetic patients. The data were collected from 1967 to 1989 in four Dutch general practices performing the Continuous Morbidity Registration Nijmegen. Each newly diagnosed Type 2 diabetic patient fulfilling the WHO criteria (n = 265) was matched to a control patient for practice, sex, age, and social class. Inclusion started in 1967, the first year of the still ongoing, Continuous Morbidity Registration Nijmegen. On average, a follow-up of 6.8 years (range 1 month-22 years) was realized. Compared to the non-diabetic control patients, the Type 2 diabetic patients showed higher cardiovascular morbidity (risk ratio 1.76, 95% CI 1.34-2.30) and a higher mortality rate (risk ratio 1.54, 95% CI 1.07-2.23). Mortality after 10 years was 36% vs 20% (p < 0.01), the median survival time 16 years vs 19 years. The cumulative survival rates were significantly different (p < 0.01) between patients and controls in the age group 65-74 years. The higher mortality in Type 2 diabetic patients was completely due to an excess of cardiovascular death (risk ratio 2.05, 95% CI 1.24-3.37).