Racial Differences in Malignant Left Ventricular Hypertrophy and Incidence of Heart Failure

Abstract

Background: A malignant subphenotype of left ventricular hypertrophy (LVH) has been described, in which minimal elevations in cardiac biomarkers identify individuals with LVH at high risk for developing heart failure (HF). We tested the hypothesis that a higher prevalence of malignant LVH among blacks may contribute to racial disparities in HF risk. Methods: Participants (n=15 710) without prevalent cardiovascular disease were pooled from 3 population-based cohort studies, the ARIC Study (Atherosclerosis Risk in Communities), the DHS (Dallas Heart Study), and the MESA (Multi-Ethnic Study of Atherosclerosis). Participants were classified into 3 groups: those without ECG-LVH, those with ECG-LVH and normal biomarkers (hs-cTnT (high sensitivity cardiac troponin-T) <6 ng/L and NT-proBNP (N-terminal pro-B-type natriuretic peptide) <100 pg/mL), and those with ECG-LVH and abnormal levels of either biomarker (malignant LVH). The outcome was incident HF. Results: Over the 10-year follow-up period, HF occurred in 512 (3.3%) participants, with 5.2% in black men, 3.8% in white men, 3.2% in black women, and 2.2% in white women. The prevalence of malignant LVH was 3-fold higher among black men and women versus white men and women. Compared with participants without LVH, the adjusted hazard ratio for HF was 2.8 (95% CI, 2.1–3.5) in those with malignant LVH and 0.9 (95% CI, 0.6–1.5) in those with LVH and normal biomarkers, with similar findings in each race/sex subgroup. Mediation analyses indicated that 33% of excess hazard for HF among black men and 11% of the excess hazard among black women was explained by the higher prevalence of malignant LVH in blacks. Of black men who developed HF, 30.8% had malignant LVH at baseline, with a corresponding population attributable fraction of 0.21. The proportion of HF cases occurring among those with malignant LVH, and the corresponding population attributable fraction, were intermediate and similar among black women and white men and lowest among white women. Conclusions: A higher prevalence of malignant LVH may in part explain the higher risk of HF among blacks versus whites. Strategies to prevent development or attenuate risk associated with malignant LVH should be investigated as a strategy to lower HF risk and mitigate racial disparities.