Association of Cardiac Injury and Malignant Left Ventricular Hypertrophy With Risk of Heart Failure in African Americans: The Jackson Heart Study.

Importance: African Americans have a higher burden of heart failure (HF) risk factors and clinical HF than other racial/ethnic groups. However, the factors underlying the transition from at-risk to clinical HF in African Americans are not well understood. Objective: To evaluate the contributions of left ventricular hypertrophy (LVH) and subclinical myocardial injury as determined by abnormal high-sensitivity cardiac troponin-I (hs-cTnI) measurements toward HF risk among African Americans. Design, Setting, and Participants: This prospective, community-based cohort study was conducted between July 2016 and September 2018 and included African American participants from Jackson, Mississippi enrolled in the Jackson Heart Study without prevalent HF who had hs-cTnI measurements and an echocardiographic examination at baseline. Participants were stratified into categories based on the presence or absence of LVH and subclinical myocardial injury (category 1: hs-cTnI <4 ng/L in women and <6 ng/L in men; category 2: 4-10 ng/L in women and 6-12 ng/L in men; category 3: >10 ng/L in women and >12 ng/L in men). Main Outcomes and Measures: Adjusted associations between LVH, subclinical myocardial injury, and the risk of incident HF hospitalization were assessed using Cox proportional hazards models. Results: The study included 3987 participants (2552 women [64%]; 240 (6.0%) with LVH; 1003 (25.1%) with myocardial injury) with 285 incident HF events over a median follow-up of 9.8 years (interquartile range, 8.9-10.6 years). In adjusted analyses, higher LV mass and subclinical myocardial injury were independently associated with the risk of HF with a significant interaction between the 2 (Pint < 0.001). The highest risk of HF was noted among individuals with both LVH and myocardial injury (absolute incidence, 35%; adjusted hazard ratio [aHR; vs no LVH and no myocardial injury], 5.35; 95% CI, 3.66-7.83). A significant interaction by sex was also observed. Men with LVH and subclinical myocardial injury had an almost 15-fold higher risk of HF (aHR, 14.62; 95% CI, 7.61-28.10) vs those with neither LVH nor injuries. By contrast, women with this phenotype had a nearly 4-fold higher risk of HF (aHR, 3.81; 95% CI, 2.40-6.85). Conclusions and Relevance: The combination of LVH and subclinical myocardial injury identifies a malignant, preclinical HF phenotype in African Americans with a very high risk of HF, particularly among men. This finding could have implications for future screening strategies that are designed to prevent HF in the population.