Association of Ischemic and Bleeding Events With Mortality Among Patients in Sweden With Recent Acute Myocardial Infarction Receiving Antithrombotic Therapy

IMPORTANCE: Antithrombotic treatment after myocardial infarction (MI) should be individualized based on the patient’s risk of ischemic and bleeding events. Uncertainty remains regarding the relative prognostic importance of the 2 types of events, and further study would be useful. OBJECTIVES: To compare the association of ischemic vs bleeding events with mortality in patients with a recent MI and assess whether the relative mortality risk for the 2 types of events has changed over the past 2 decades. DESIGN, SETTING, AND PARTICIPANTS: A cohort study based on nationwide registers in Sweden, 2012-2017, was conducted. Data were analyzed between July 2021 and May 2022. Patients with MI who were discharged alive with antithrombotic therapy (antiplatelet therapy or oral anticoagulation) were included in the analysis. MAIN OUTCOMES AND MEASURES: The incidence of a first ischemic event (hospitalization for MI or ischemic stroke) or bleeding event (hospitalization with bleeding) up to 1 year after discharge and the mortality risk up to 1 year after each type of event were assessed. Cox proportional hazards regression models were used to estimate adjusted hazard ratios (aHRs) for 1-year mortality after an ischemic and bleeding event vs no event, and after an ischemic vs bleeding event. Adjusted HRs for mortality after ischemic vs bleeding events were compared among patients discharged in 1997-2000, 2001-2011, and 2012-2017. RESULTS: Of 86 736 patients discharged after MI in 2012-2017 (median age, 71 [IQR, 62-80] years; 57 287 [66.0%] men), 4039 individuals experienced a first ischemic event (5.7 per 100 person-years) and 3399 experienced a first bleeding event (4.8 per 100 person-years). The mortality rate was 46.2 per 100 person-years after an ischemic event and 27.1 per 100 person-years after a bleeding event. The aHR for 1-year mortality vs no event was 4.16 (95% CI, 3.91-4.43) after an ischemic event and 3.43 (95% CI, 3.17-3.71) after a bleeding event. When the 2 types of events were compared, the aHR was 1.27 (95% CI, 1.15-1.40) for an ischemic vs bleeding event. There was no statistically significant difference in the aHR of an ischemic vs bleeding event in 1997-2000, 2001-2011, and 2012-2017. CONCLUSIONS AND RELEVANCE: In this nationwide cohort study of patients with a recent MI, postdischarge ischemic events were more common and associated with higher mortality risk compared with bleeding events.