Modifiable factors impact intracerebral hemorrhage risk in Black, Hispanic people

Intracerebral hemorrhage disproportionately affected and occurred earlier in uninsured Black and Hispanic people with untreated hypertension, according to study data published in JAMA Network Open.

“There are important gaps in our understanding of the risk factors for [intracerebral hemorrhage (ICH)] among Black and Hispanic patients,” Steven J. Kittner, MD, MPH, professor of neurology and epidemiology and public health at University of Maryland, and colleagues wrote. “Prior studies have been relatively small, with limited precision of the association of risk factors with ICH. We need precise estimates of risk factor prevalence and strength of association to determine the population-level impact of risk factors.”

Kittner and colleagues collected and prospectively reviewed data from 3,000 patients with ICH and 3,000 matched control participants recruited from 42 U.S. hospitals between September 2009 and July 2016. The ICH cohort comprised 1,000 Black patients (median age, 57 years; 42.5% women), 1,000 Hispanic patients (median age, 58 years; 37.3% women) and 1,000 white patients (median age, 71 years; 43.7% women).

Study data showed 8.7% of white patients had ischemic stroke compared with 9.9% in both Black and Hispanic patients. Further, Black and Hispanic patients with ICH were more likely than white patients to have chronic kidney disease (10.7% vs. 9.5% vs. 5.7%), untreated hypertension (37.1% vs. 37% vs. 23.3%) and diabetes (24.2% vs. 31% vs. 21.1%). Researchers also observed heavier alcohol use in Black (11.4%) and Hispanic patients (11.7%), compared with white patients (6.9%), and more cocaine or amphetamine use (7.2% vs. 3.8% vs. 1.8%).

Lack of insurance was also higher in Black (33.2%) and Hispanic (38.7%) patients than white patients (11.2%). Not having insurance was disproportionately associated with population attributable risk (PAR) percentages among Black (21.7%; 95% CI, 17.5-25.7) and Hispanic patients (30.2%; 95% CI, 26.1-34.1) compared with white patients (5.8%; 95% CI, 3.3-8.2).

While Black patients had higher rates of APOE e4 proportion (39.3%), Hispanic participants had the lowest APOE e2 proportion (7.2%).

APOE e2 and APOE e4 increased lobar ICH risk. Heavy alcohol use increased nonlobar ICH, while high cholesterol and current and former smoking lowered it.

Ischemic stroke history, chronic kidney disease, hypertension, cocaine or amphetamine use and lack of insurance, which were highest among Black and Hispanic participants, increased lobar and nonlobar ICH risk. Low BMI, obstructive sleep apnea risk and anticoagulant use, the latter of which was most prevalent among white patients (14.2%), also increased ICH risk.

According to the investigators, “Lack of medical insurance was associated with a similar degree of risk as cocaine, amphetamine, or anticoagulation use in each race/ethnic group but was associated with a much higher PAR percentage in Black and Hispanic participants.”

Study strengths included large and equal sample sizes of racial and ethnic groups, matched control participants, phenotyping of lobar and nonlobar ICH, standardized interview for risk factors, centralized neuroimaging and external validity analysis. Study limitations included design, potential biases and specificity to the U.S.

“Future research using mendelian randomization methods are needed to confirm the findings in white populations and determine whether a similar association is present in Black and Hispanic populations,” Kittner and colleagues wrote.