Prognostic value of elevated trimethylamine-N-oxide levels in patients with coronary artery disease in China

Background Coronary artery disease (CAD) is a prevalent cardiovascular condition worldwide. Trimethylamine N-oxide (TMAO), a metabolite produced by gut microbiota, plays a crucial role in the pathogenesis and progression of CAD. However, the long-term prognostic value of plasma TMAO for all-cause mortality in Chinese CAD patients remains to be fully explored. Methods In this observational cohort study, 389 hospitalized CAD patients, confirmed via coronary angiography at Xiangya Hospital in 2022, were enrolled. Plasma TMAO levels were measured using liquid chromatography-tandem mass spectrometry. All-cause mortality events were identified through telephone interviews, hospital outpatient visits, and official hospital records, conducted semi-annually. Kaplan-Meier analysis and Cox regression analysis were employed to investigate the relationship between TMAO levels and all-cause mortality. Results Among 364 CAD patients who completed the median follow-up period of 39 months (IQR: 37–42 months), 40 patients (11.0%) experienced all-cause mortality. Patients with elevated TMAO levels, based on the optimal cutoff value of 317.62 ng/mL, had a significantly higher mortality rate compared to those with lower levels ( P  < 0.0001). After adjusting for conventional risk factors, including diabetes, elevated TMAO levels remained a significant predictor of all-cause mortality (hazard ratio [HR] 2.626; 95% CI: 1.361 to 5.065; P  = 0.004). Conclusions Elevated plasma TMAO levels are significantly associated with increased all-cause mortality over a median follow-up of 39 months in CAD patients from China.