The correlation between plasma trimethylamine N-oxide level and heart failure classification in northern Chinese patients

Background: Trimethylamine N-oxide (TMAO) has been identified as a new biomarker of cardiovascular disease. Our aim was to evaluate the plasma levels of TMAO in patients with or without heart failure (HF), and to indicate the correlation between plasma TMAO level and HF classification in northern Chinese patients. Methods: A total of 112 control participants and 184 HF patients participated in this study. Plasma levels of TMAO and N-terminal probrain natriuretic peptide (NT-proBNP) in all participants were examined and analyzed. Results: The plasma TMAO levels were remarkably higher in HF patients than that in control participants (7.0 +/- 0.6 vs. 1.5 +/- 0.1 mu mol/L; P<0.01). In addition, the plasma TMAO levels of significantly increased from NYHA II to NYHA IV group (3.5 +/- 0.9, 6.0 +/- 0.8 and 8.1 +/- 1.0 mu mol/L, respectively). The receiver operating characteristic analysis (ROC) showed that area under the curve (AUC) of TMAO was 0.881 (P<0.01). Furthermore, the AUC value for TMAO was 0.857 (95% CI: 0.6741.000; P<0.01), 0.845 (95% CI: 0.7780.911; P<0.01) and 0.914 (95% CI: 0.8720.956; P<0.01) in NYHA II, NYHA III and NYHA IV groups, respectively. Univariate and multivariate logistic regression analysis indicated that TMAO was an independent risk factor for HF in patients. The level of TMAO was positively correlated with NT-proBNP. However, the diagnostic ability of TMAO was lower than that of NT-proBNP. Conclusions: TMAO was an independent predictor of HF, moreover, the TMAO levels were highly associated with HF classification in northern Chinese patients.