Background: Diabetes is a cardiovascular disease risk factor that exerts a higher risk for coronary heart disease and stroke among females compared to males. Outcomes after first stroke in those with diabetes are not well characterized, especially by sex and age, and studies have been limited by short follow-up and biased samples. We sought to calculate the sex- and age-specific risk of cardiovascular outcomes after ischemic stroke among those with diabetes using a study with full population coverage.
Methods: Using population-based demographic and administrative health care databases in Ontario, Canada, we selected all patients with diabetes hospitalized with first ischemic stroke between 4/1/2002 and 3/31/2012. Participants were followed for death, stroke, and myocardial infarction (MI). Kaplan-Meier survival analysis and Fine-Gray competing risk models were used to estimate hazards and adjusted hazards of outcomes by sex and age strata. Models were adjusted for demographics and vascular risk factors. Sensitivity analysis including adjustment for medication use was performed in those aged >=65 years.
Results: There were 25495 ischemic stroke patients with diabetes. The incidence of death was higher in women than in men (14.08 per 100 person-years [95% CI 13.73-14.44] vs. 11.89 [11.60-12.19]), but was lower after adjustment for age and other risk factors (adjusted hazard ratio [HR] 0.95 [0.92-0.99]). The incidence of recurrent stroke was similar in women and men, but men were more likely to be readmitted for MI (1.99 per 100 person-years [1.89-2.10] vs 1.58 [1.49-1.68] among females). In multivariable models, females had a lower risk of readmission for any event (HR 0.96 [95% CI 0.93-0.99]).
Conclusions: In this retrospective study with full population coverage among diabetics with index stroke in Ontario, there was a higher unadjusted rate of death among females compared to males, and higher unadjusted incidence of MI among males. In adjusted models, females had a lower risk of death compared to males, although the increased risk of MI among males persisted. These findings confirm and quantify sex differences in outcomes after stroke in patients with diabetes.