Evaluation of low-dose aspirin for primary prevention of ischemic stroke among patients with diabetes: a retrospective cohort study

Background Low-dose aspirin is recommended to reduce the risk of cardiovascular disease. However, the questions with regard to primary prevention have been raised among patients with diabetes. We evaluated low-dose aspirin use for preventing ischemic stroke in patients with diabetes using a national health insurance database. Methods Using data from the Korean Health Insurance Review and Assessment Service database from January 1, 2005, through December 31, 2009, a population-based retrospective cohort study was conducted with incident patients with diabetes aged 40 to 99 years old with the initial use of low-dose aspirin during the index period from January 1, 2006 to December 31, 2007. We matched each low-dose aspirin user to one non-user using a propensity score. The Cox proportional hazards model was used to compare the risk of hospitalization for ischemic stroke in users and nonusers of low-dose aspirin until December 31, 2009. Results Out of 261,065 incident patients with diabetes, 15,849 (6.2%) were low-dose aspirin users. Compared to non-users, the adjusted hazard ratio (95% confidence interval) of low-dose aspirin users for hospitalization due to ischemic stroke was 1.73 (95% CI; 1.41-2.12). In a sensitivity analysis of study subjects with more than 1 year follow-up periods, slightly higher adjusted hazard ratio (1.97, 95% CI; 1.51-2.62) was observed. In the subgroup analyses, there were no significant changes in the risk of hospitalization for ischemic stroke irrespective of gender, age, or comorbidity. Conclusions In this study of patients with diabetes, the use of low-dose aspirin showed an increased risk of hospitalization for ischemic stroke. These results suggest that low-dose aspirin use for the primary prevention of ischemic stroke should be reconsidered in patients with diabetes.