All-Cause Mortality and Trimethylamine N-Oxide Levels in Patients with Cardiovascular Disease

Abstract

<b><i>Introduction:</i></b> Trimethylamine N-oxide (TMAO) is an organic compound with a well-established involvement in the pathogenesis of cardiovascular disease (CVD). However, data on the links between TMAO levels and cardiovascular mortality in Polish patients are lacking. <b><i>Objectives:</i></b> We aimed to assess the relationship between serum TMAO levels and 5-year mortality in Polish patients with CVD. <b><i>Patients and Methods:</i></b> We retrospectively assessed serum TMAO levels in 1,036 consecutive patients (median age, 62 years; men, 61%) hospitalized between 2013 and 2015. Correlations between TMAO levels and 5-year mortality as well as anthropometric and biochemical parameters were assessed for the whole population and the subgroups of patients with acute coronary syndrome, stable coronary syndrome (SCS), chronic heart failure (HF), and atrial fibrillation (AF). <b><i>Results:</i></b> In the univariate analysis, increased TMAO levels predicted 5-year mortality without clinically significant power (hazard ratio [HR], 1.01; 95% CI: 1.006–1.018; <i>p</i> &#x3c; 0.0001). However, even this weak effect was lost in the multivariate analysis after adjustment for age, sex, comorbidities, and laboratory parameters. In the whole study group, TMAO levels in the fourth quartile of concentration (&#x3e;6.01 µM) predicted 5-year mortality only in the univariate analysis (HR: 1.55; 95% CI: 1.34–1.79; <i>p</i> &#x3c; 0.0001). In subgroup univariate analysis, TMAO levels predicted 5-year mortality in patients with SCS, chronic HF, and AF. <b><i>Conclusions:</i></b> Despite the promising results of previous studies, our study shows that the level of TMAO has at most moderate value in predicting all-cause mortality. TMAO levels depend on other clinical variables, which limits the use of TMAO as an independent predictor of mortality in these patients.