Risk of bleeding after hospitalization for a serious coronary event: a retrospective cohort study with nested case-control analyses

BACKGROUND Bleeding events have been associated with the use of antiplatelet agents. This study estimated the incidence of bleeding events in patients previously hospitalized for a serious coronary event and determined the risks of bleeding associated with the use of acetylsalicylic acid (ASA) and/or clopidogrel. METHODS A UK primary care database was used to identify 27,707 patients aged 50 to 84 years, hospitalized for a serious coronary event during 2000 to 2007 and who were alive 30 days later (start date). Patients were followed up until they reached an endpoint (hemorrhagic stroke, upper or lower gastrointestinal bleeding [UGIB/LGIB]), death or end of study [June 30, 2011]) or met an exclusion criterion. Risk factors for bleeding were determined in a nested case-control analysis. RESULTS Incidences of hemorrhagic stroke, UGIB, and LGIB were 5.0, 11.9, and 25.5 events per 10,000 person-years, respectively, and increased with age. UGIB and LGIB led to hospitalization in 73 and 23 % of patients, respectively. Non-users of ASA, who were mostly discontinuers, and current users of ASA had similar risks of hemorrhagic stroke, UGIB, and LGIB. Users of combined antithrombotic therapy (warfarin and antiplatelets) experienced an increased risk of hemorrhagic stroke (odds ratio [OR], 6.36; 95 % confidence interval [CI], 1.34-30.16), whereas users of combined antiplatelet therapy (clopidogrel and ASA) experienced an increased risk of UGIB (OR, 2.42; 95 % CI, 1.09-5.36). An increased risk of LGIB (OR, 1.86; 95 % CI, 1.34-2.57) was also observed in users of clopidogrel. CONCLUSIONS In patients previously hospitalized for a serious coronary event, combined antithrombotic therapy was associated with an increased risk of hemorrhagic stroke, whereas combined antiplatelet therapy was associated with an increased risk of UGIB.Non-use of ASA was rare in this population and use of ASA was not associated with a significantly increased risk of hemorrhagic stroke, UGIB, or LGIB.