Mortality from cerebrovascular disease in a cohort of 23 000 patients with insulin-treated diabetes.

BACKGROUND AND PURPOSE Disease of the cardiovascular system is the main cause of long-term complications and mortality in patients with type I (insulin-dependent) and type II (non-insulin-dependent) diabetes. Cerebrovascular mortality rates have been shown to be raised in patients with type II diabetes but have not previously been reported by age and sex in patients with type I diabetes. METHODS A cohort of 23 751 patients with insulin-treated diabetes, diagnosed under the age of 30 years from throughout the United Kingdom, was identified during 1972 to 1993 and followed up for mortality until the end of December 2000. Age- and sex-specific mortality rates and standardized mortality ratios (SMRs) were calculated. RESULTS There were 1437 deaths during the follow-up, 80 due to cerebrovascular disease. Overall, the cerebrovascular mortality rates in the cohort were higher than the corresponding rates in the general population, and the SMRs were 3.1 (95% CI, 2.2 to 4.3) for men and 4.4 (95% CI, 3.1 to 6.0) for women. When stratified by age, the SMRs were highest in the 20- to 39-year age group. After subdivision of cause of death into hemorrhagic and nonhemorrhagic origins, there remained a significant increase in mortality from stroke of nonhemorrhagic origin. CONCLUSIONS Analyses of mortality from this cohort, essentially one of patients with type I diabetes, has shown for the first time that cerebrovascular mortality is raised at all ages in these patients. Type I diabetes is at least as great a risk factor for cerebrovascular mortality as type II diabetes.