Epidemiology and secondary prevention of ischemic stroke in patients on antiplatelet drug: a retrospective cohort study

One-third to one-half of ischemic strokes occurred in patients taking antiplatelet drugs. The optimal therapeutic strategy for antithrombotic drugs remains uncertain and guidelines provide scarse recommendation. Therefore, aims of our study were to: (i) estimate the prevalence of patients who develop an ischemic stroke while on antiplatelet drugs, (ii) investigate potential factors associated with this phenomenon, (iii) describe management strategies in daily clinical practice. Consecutive adult patients admitted for acute ischemic stroke at the academic hospital of Varese, Italy, from January 2010 till December 2011 were included. Patients were retrospectively identified by searching the administrative database of the hospital. Odds ratios (ORs) and their 95% confidence intervals (CI) for identifying factors associated with dependent variable were estimated using univariate logistic regression. Any variable with a p value<0.2 at univariate analysis was included in a multivariate model. A total of 419 patients were included. Patients with ischemic stroke while on antiplatelet drugs were 49.6%. The following baseline characteristics were associated with the occurrence of ischemic stroke in patients taking antiplatelet drugs: diabetes mellitus (DM), history of ischemic heart disease (IHD), age>65years and previous stroke or transient ischemic stroke (TIA). The following variables were significantly associated with a change of antithrombotic therapy at discharge: DM, history of IHD and previous stroke or TIA. Our study confirms that the occurrence of ischemic stroke during antiplatelet treatment is common and management of antithrombotic therapy is heterogeneous. Factors that may explain therapeutic failure include undetected cardioembolic sources, drug resistance, poor compliance, or the presence of diabetes, atherothrombotic disease, and advanced age. Randomized controlled trials are warranted to assess the optimal antithrombotic strategy for ischemic stroke occurred in patients taking antiplatelet drugs.