Effect of diabetes on hospitalization for ischemic stroke and related in-hospital mortality: a study in Tuscany, Italy, over years 2004-2011

Background: Incidence of ischemic stroke and associated in-hospital mortality is decreasing in Western populations, while the prevalence of diabetes, a well-known risk factor for ischemic stroke, is progressively rising. This study was aimed at evaluating the effect of diabetes on ischemic stroke hospitalization and in-hospital mortality after ischemic stroke.

Methods: Discharges with diagnosis of ischemic stroke were identified in a database containing all hospitalizations of resident population of Tuscany, Italy, over years 2004-2011. Cases with diabetes were identified through specific drug prescriptions, official certifications or previous hospital diagnosis. Rates of annual ischemic stroke incidence and related in-hospital mortality were separately calculated for gender and age class, in subjects with and without diabetes.

Results: Sixty-five thousand one hundred sixty-five hospital discharges with ischemic stroke diagnosis were identified. Diabetes was associated with increased risk of stroke odds ratio(95% confidence interval):1.31(1.28-1.34) in men and 1.24(1.21-1.37) in women. Diabetic women, compared with men, had a higher in-hospital mortality risk after ischemic stroke (odds ratio:1.32; 1.06-1.64), whereas in non-diabetic subjects, there was no difference between genders. Incidence of ischemic stroke has declined in non-diabetic subjects, except for women aged ≤70 years; a similar reduction was observed for in-hospital mortality. Among diabetic patients, conversely, annual incidence of ischemic stroke rose by 3% in the elderly people (>70 years), and annual mortality trend remained unchanged.

Conclusions: In the last decade, the incidence of ischemic stroke and of related in-hospital mortality declined in persons without diabetes, while increasing among diabetic patients of advanced age. Women with diabetes, compared with men, had a higher in-hospital mortality risk.