Ethnic differences in association of outcomes with trimethylamine N‐oxide in acute heart failure patients

Abstract Aims The aim of this study was to investigate whether ethnicity influences the associations between trimethylamine N‐oxide (TMAO) levels and heart failure (HF) outcomes. Methods and results Trimethylamine N‐oxide levels were measured in two cohorts with acute HF at two sites. The UK Leicester cohort consisted mainly of Caucasian (n = 842, 77%) and South Asian (n = 129, 12%) patients, whereas patients in the Japanese cohort (n = 116, 11%) were all Japanese. The primary endpoint was the measurement of all‐cause mortality and/or HF rehospitalization within 1 year post‐admission. Association of TMAO levels with outcome was compared in the entire population and between ethnic groups after adjustment for clinical parameters. TMAO levels were significantly higher in Japanese patients [median (interquartile range): 9.9 μM (5.2–22.8)] than in Caucasian [5.9 μM (3.6–10.8)] and South Asian [4.5 μM (3.1–8.4)] (P