Cardiovascular risk factors and 5-year mortality in the Copenhagen Stroke Study

Abstract

Background: The treatment of cardiovascular risk factors has improved over the recent years and may have improved survival. The aim of this study was to investigate the up-to-date prognostic significance of cardiovascular risk factors for 5-year survival in a large unselected ischemic stroke population.

Methods: We studied 905 ischemic stroke patients from the community-based Copenhagen Stroke Study. Patients had a CT scan and stroke severity was measured by the Scandinavian Stroke Scale on admission. A comprehensive evaluation was performed by a standardized medical examination and questionnaire for cardiovascular risk factors, age, and sex. Follow-up was performed 5 years after stroke, and data on mortality were obtained for all, except 6, who had left the country. Five-year mortality was calculated by the Kaplan-Meier procedure and the influence of multiple predictors was analyzed by Cox proportional hazards analyses adjusted for age, gender, stroke severity, and risk factor profile.

Results: In Kaplan-Meier analyses atrial fibrillation (AF), ischemic heart disease, diabetes, and previous stroke were associated with increased mortality, while smoking and alcohol intake were associated with decreased mortality. No association was found for hypertension or intermittent claudication. In the final Cox proportional hazard model predictors of 5-year mortality were AF (hazard ratio, HR 1.4; 95% CI 1.1-1.7), diabetes (HR 1.3; 95% CI 1.0-1.6), smoking (HR 1.2; 95% CI 1.0-1.4), and previous stroke (HR 1.4; 95% CI 1.1-1.7), after adjustment for age, gender, and stroke severity.

Conclusions: AF, diabetes, smoking, and previous stroke significantly affect long-term survival. Although smoking and daily alcohol consumption appeared to be associated with improved survival in the univariate analyses, adjustment for other factors and especially age revealed the lethal effect of smoking, while the positive effect of alcohol disappeared. More focus on secondary preventive measures, such as anticoagulation for AF, smoking cessation, and proper treatment of diabetes may significantly improve long-term survival.