Contribution of Racial and Ethnic Differences in Cerebral Small Vessel Disease Subtype and Burden to Risk of Cerebral Hemorrhage Recurrence

Abstract

Objective: Black and Hispanic survivors of intracerebral hemorrhage (ICH) are at higher risk of recurrent intracranial bleeding. MRI-based markers of chronic cerebral small vessel disease (CSVD) are consistently associated with recurrent ICH. We therefore sought to investigate whether racial/ethnic differences in MRI-defined CSVD subtype and severity contribute to disparities in ICH recurrence risk.

Methods: We analyzed data from the Massachusetts General Hospital ICH study (n = 593) and the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study (n = 329). Using CSVD markers derived from MRIs obtained within 90 days of index ICH, we classified ICH cases as cerebral amyloid angiopathy (CAA)-related, hypertensive arteriopathy (HTNA)-related, and mixed etiology. We quantified CSVD burden using validated global, CAA-specific, and HTNA-specific scores. We compared CSVD subtype and severity among White, Black, and Hispanic ICH survivors and investigated its association with ICH recurrence risk.

Results: We analyzed data for 922 ICH survivors (655 White, 130 Black, 137 Hispanic). Minority ICH survivors had greater global CSVD (p = 0.011) and HTNA burden (p = 0.021) on MRI. Furthermore, minority survivors of HTNA-related and mixed-etiology ICH demonstrated higher HTNA burden, resulting in increased ICH recurrence risk (all p < 0.05).

Conclusions: We uncovered significant differences in CSVD subtypes and severity among White and minority survivors of primary ICH, with direct implication for known disparities in ICH recurrence risk. Future studies of racial/ethnic disparities in ICH outcomes will benefit from including detailed MRI-based assessment of CSVD subtypes and severity and investigating social determinants of health.

Figure 1. Flowchart of Participant Enrollment From the ERICH and MGH-ICH Studies

ERICH = Ethnic/Racial Variations of Intracerebral Hemorrhage; ICH = intracerebral hemorrhage; LTFU = lost to follow-up; MGH = Massachusetts General Hospital.

Figure 2. CAA and HTNA Small Vessel Disease Severity Across Racial/Ethnic Groups

Graph presents stacked column plots of cerebral amyloid angiopathy (CAA) and hypertensive arteriopathy (HTNA) small vessel disease scores on MRI among survivors of CAA-related, HTNA-related, and mixed-etiology intracerebral hemorrhage (ICH) cases with comparison between White and minority (Black or Hispanic) groups. For each score value, the column labels report the percentage of patients in the group of interest. Total sample size in each group is presented below the columns. Comparison of score distribution between White and minority participants in each group resulted in the p values presented above each pair of columns.

Figure 3. ICH Recurrence Risk Based on Small Vessel Disease Severity and Race/Ethnicity

Kaplan-Meier plot of intracerebral hemorrhage (ICH) recurrence risk across study sub-groups identified based on race/ethnicity, i.e., White vs Black or Hispanic, and cerebral small vessel disease (CSVD) severity, defined using the global MRI burden score values as high burden (score >2) vs low burden (score 0–2). Cutoff global CSVD burden score value of 2 was selected because it represents the median value in the overall study dataset. Sample size in the study during follow-up is presented above the horizontal axis (marked n). *p < 0.01 for comparison of groups (log-rank test); **p < 0.001 for comparison of groups (log-rank test).