Intracerebral hemorrhage increases risk for ischemic stroke, myocardial infarction

Intracerebral hemorrhage correlated with an increased risk for ischemic stroke and myocardial infarction, according to results from an analysis of four population-based, U.S. cohort studies that was published in JAMA Neurology.

The findings indicated that intracerebral hemorrhage “may be a novel risk marker for arterial ischemic events,” according to the researchers.

“Large case series have indicated that myocardial infarction and ischemic stroke are not uncommon after intracerebral hemorrhage, but these prior studies lacked control groups without intracerebral hemorrhage,” the researchers wrote. “Therefore, to our knowledge, it remains unknown whether intracerebral hemorrhage is associated with a higher risk of subsequent myocardial infarction and ischemic stroke.”

Santosh B. Murthy, MD, MPH, medical director of the neurosciences intensive care unit at New York-Presbyterian Hospital/Weill Cornell and assistant professor of neurology at Weill Cornell Medical College, and colleagues analyzed the correlation between intracerebral hemorrhage and arterial ischemic events using pooled data from four population-based, U.S. studies. The studies included the Atherosclerosis Risk in Communities (ARIC) study, the Cardiovascular Health Study (CHS), the Northern Manhattan Study (NOMAS), and the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.

The researchers examined data from patients enrolled between 1987 and 2007, with the last available follow-up data from December 31, 2018. Murthy and colleagues conducted a data analysis between September 2019 and March 2020.

The occurrence of an arterial ischemic event, which was defined as a composite of ischemic stroke or myocardial infarction that was centrally adjudicated within each study, served as the primary outcome. Secondary outcomes included ischemic stroke and myocardial infarction, according to the study results. Murthy and colleagues excluded participants with a prevalent intracerebral hemorrhage, ischemic stroke or myocardial infarction at their baseline study visit. They used Cox proportional hazards regression to look at the link between intracerebral hemorrhage and subsequent arterial ischemic events after adjusting for baseline age, sex, race/ethnicity, vascular comorbidities and the use of antithrombotic medications.

Of 55,131 total participants, Murthy and colleagues included 47,866 in their analysis (57.7% women; mean age, 62.2 years).

The study period included 318 intracerebral hemorrhages and 7,648 arterial ischemic events over a median follow-up period of 12.7 years. Murthy and colleagues reported an incidence of an arterial ischemic event of 3.6 events per 100 person-years (95% CI, 2.7-5 events per 100 person-years) following intracerebral hemorrhage compared with 1.1 events per 100 person-years (95% CI, 1.1-1.2 events per 100 person-years) among those without intracerebral hemorrhage. In adjusted models, intracerebral hemorrhage correlated with arterial ischemic events (HR = 2.3; 95% CI, 1.7-3.1), ischemic stroke (HR = 3.1; 95% CI, 2.1-4.5) and myocardial infarction (HR = 1.9; 95% CI, 1.2-2.9).

In sensitivity analyses, the researchers found that intracerebral hemorrhage correlated with arterial ischemic events in the following scenarios: when covariates were updated in a time-varying manner (HR = 2.2; 95% CI, 1.6-3); when they used incidence density matching (OR = 2.3; 95% CI, 1.3-4.2); when they included participants with prevalent intracerebral hemorrhage, ischemic stroke or myocardial infarction (HR = 2.2; 95% CI, 1.6-2.9); and when they used death as a competing risk (subdistribution HR = 1.6; 95% CI, 1.1-2.1).

“These findings suggest that intracerebral hemorrhage may be a novel risk marker for arterial ischemic events,” Murthy and colleagues wrote.