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Introduction: Ischemic stroke and myocardial infarction (MI) have been reported as frequent complications after intracerebral hemorrhage (ICH), but the magnitude and duration of this risk is unclear.Methods: We performed a cohort-crossover study using inpatient and outpatient claims data from a nationally representative 5% sample of Medicare beneficiaries from 2008 through 2014. We included patients ≥66 years of age hospitalized for ICH. Our primary outcome was a composite of ischemic stroke or MI. We used validated ICD-9-CM diagnosis codes to identify predictors and outcomes. To avoid inclusion of patients with ICH as a complication of stroke or MI, we excluded ICH patients with a concurrent stroke or MI during the index ICH hospitalization. We compared the risk of stroke and MI during the 12 weeks after ICH versus the corresponding 12-week period 6 months later. To avoid immortal time bias, we limited our cohort to patients who remained alive and insured throughout the 9-month study period. Odds ratios (OR) and absolute risk differences were calculated using the Mantel-Haenszel estimator for matched data.Results: We included 1,817 ICH patients. In the 12-week period after discharge, 130 (7.1%) patients had a stroke or MI versus 13 (0.7%) in the corresponding 12-week period 6 months later. The absolute risk increase for ischemic stroke or MI was 6.4% (95% CI, 5.1-7.7%) during this period, with a corresponding OR of 10.0 (95% CI, 5.6-19.3). The absolute risk increase was 4.8% (95% CI, 3.7-5.8%) during the first 4 weeks, and 1.0% (95% CI, 0.3-1.7%) during weeks 5-8.Limitations: First, we lacked data on antithrombotic drug use, so further work is needed to distinguish how much of the heightened risk was due to the effect of ICH versus the effect of antithrombotic cessation. Second, we included only patients who survived at least 9 months; however, this would be expected to select for a less sick cohort and therefore decrease any apparent associations with these serious complications.Conclusions: There appears to be a heightened short-term risk of arterial thromboembolic events after acute ICH. This underlines the importance of studies and trials to identify optimal strategies for resuming antithrombotic medications in survivors of ICH.