Abstract

Aims Ethnicity can influence patient outcomes and treatment efficacy, but knowledge is limited on how multimorbidity interacts with clinical events, for example when heart failure (HF) and atrial fibrillation (AF) combine. Methods and Results 16 713 patients were included from 12 randomized placebo-controlled trials in HF (11 vs beta-blockers and 1 vs spironolactone), of which 13 568 patients (81.2%) were in sinus rhythm and 3145 (18.8%) had comorbid AF at baseline. Non-white ethnicity was recorded in 1899 (11%), with these patients being younger than those of white ethnicity (median age 58 vs 67 years), higher rates of diabetes and hypertension, and lower left-ventricular ejection fraction (median 25% vs 30%). During median follow-up of 1.4 years (interquartile range 0.8–2.3), the primary outcome of all-cause mortality occurred in 394 (21%) non-white patients and 2142 (15%) white patients, with confounder-adjusted hazard ratio (HR) 1.36, 95% CI 1.20–1.54; P < .001. The impact of ethnicity on death was greater in patients with coexisting HF and AF (non-white vs white HR 2.05; 95% CI 1.55–2.70; P < .001) than in those with HF in sinus rhythm (HR 1.24; 95% CI 1.08–1.41; P = .002). The interaction P-value was .003, and confirmed using propensity-score matching to account for baseline differences (P = .009). Similar disparities with ethnicity were seen for the secondary outcomes of cardiovascular and HF-related death, and cardiovascular and HF-related hospitalization. Conclusion Non-white patients with HF and reduced ejection fraction suffer from substantially higher rates of death than white patients, with comorbid atrial fibrillation leading to significant worsening of this ethnicity-related disparity.