Abstract
IMPORTANCE: Patients with stroke due to nontraumatic (spontaneous) intracerebral hemorrhage (ICH) often harbor vascular risk factors and comorbidities, but it is unclear which major adverse cardiovascular events (MACEs) occur more frequently among patients with a prior ICH than the general population. OBJECTIVE: To evaluate the risk of a MACE for patients with a prior ICH compared with the general population. DESIGN, SETTING, AND PARTICIPANTS: This cohort study identified 8991 patients with a first ICH in the Danish Stroke Registry from January 1, 2005, to June 30, 2018, who were aged 45 years or older and survived more than 30 days after an ICH. Patients in this ICH cohort were matched 1:40 on age, sex, and ICH-onset date with a comparison cohort of 359 185 individuals from the general population without a prior ICH. Both cohorts were followed up for 6 months or more until December 31, 2018, for outcomes using registry data. Data were analyzed from October 1, 2021, to July 19, 2022. EXPOSURES: Intracerebral hemorrhage identified by a nationwide clinical database. MAIN OUTCOMES AND MEASURES: The main outcomes were ICH, ischemic stroke, myocardial infarction, and a composite of MACEs. For each outcome, a case-control study nested within the cohorts was also performed, adjusting for time-varying exposures and potential confounders. Crude absolute event rates per 100 person-years, adjusted hazard ratios (aHRs) and 95% CIs and, in the nested case-control analyses, crude and adjusted odds ratios and 95% CIs were calculated. RESULTS: The ICH cohort (n = 8991; 4814 men [53.5%]; mean [SD] age, 70.7 [11.5] years) had higher event rates than the comparison cohort (n = 359 185; 192 256 men [53.5%]; mean [SD] age, 70.7 [11.5] years) for MACEs (4.16 [95% CI, 3.96-4.37] per 100 person-years vs 1.35 [95% CI, 1.33-1.36] per 100 person-years; aHR, 3.13 [95% CI, 2.97-3.30]), ischemic stroke (1.52 [95% CI, 1.40-1.65] per 100 person-years vs 0.56 [95% CI, 0.55-0.57] per 100 person-years; aHR, 2.64 [95% CI, 2.43-2.88]), and ICH (1.44 [95% CI, 1.32-1.56] per 100 person-years vs 0.06 [95% CI, 0.06-0.07] per 100 person-years; aHR, 23.49 [95% CI, 21.12-26.13]) but not myocardial infarction (0.52 [95% CI, 0.45-0.60] per 100 person-years vs 0.48 [95% CI, 0.47-0.49] per 100 person-years; aHR, 1.12 [95% CI, 0.97-1.29]). Nested case-control analyses returned risk estimates of similar magnitude as the cohort analyses. CONCLUSIONS AND RELEVANCE: The findings of this cohort study suggest that Danish patients with a prior ICH had statistically significantly higher rates of MACEs than the general population, indicating a need for attention to optimal secondary prevention with blood pressure lowering and antithrombotic and statin therapies after an ICH in clinical research and practice.