Is diabetes mellitus a cardiovascular disease risk equivalent for fatal stroke in women? Data from the Women's Pooling Project.

BACKGROUND AND PURPOSE Diabetes mellitus is an independent risk factor for stroke and is associated with a 1.8- to approximately 6-fold increased risk compared with nondiabetic subjects. Recent guidelines have classified diabetes as a coronary heart disease risk equivalent. Whether diabetes is a cardiovascular disease risk equivalent for stroke is not established. METHODS Data were pooled from 9 prospective epidemiological studies in the United States. We followed up 27,269 women (8.5% diabetic, 2.9% with prior myocardial infarction, 2.3% with prior stroke) for an average of 8.3 years, during which 238 stroke deaths were observed. RESULTS Both diabetic subjects without cardiovascular disease and nondiabetic subjects with history of prior stroke had a significantly increased risk of 10-year stroke mortality compared with nondiabetic subjects without prior cardiovascular disease (hazard ratio [HR], 6.77; 95% confidence interval [CI], 4.56 to 10.05; HR, 3.37; 95% CI, 2.38 to 4.77). History of prior myocardial infarction was not associated with long-term stroke mortality (HR, 0.66; 95% CI, 0.27 to 1.61). After adjustment for risk factors, diabetic subjects had similar risk compared with subjects with a history of prior stroke (HR, 1.29; P=0.43). CONCLUSIONS Diabetic subjects without cardiovascular disease have a fatal stroke risk similar to that of nondiabetic subjects with a history of prior stroke and similar risk factor profile. This suggests that diabetes mellitus may be classified as a stroke risk equivalent and may warrant more aggressive treatment strategies in the future prevention of stroke.