TMAO as a biomarker of cardiovascular events: a systematic review and meta-analysis

Unmasking the residual cardiovascular risk is a major research challenge in the attempt to reduce cardiovascular disease (CVD) morbidity and mortality. Mounting evidence suggests that a high circulating level of trimethylamine N-oxide is a new potential CVD risk factor. We performed a systematic review of the published studies to clarify the association between circulating high levels of TMAO and cardiovascular events.

Studies evaluating the association between TMAO and CVD events were searched by electronic databases up to December 2018. Pooled results were expressed as risk ratio (RR) with 95% pertinent confidence interval (CI).

Three studies for a total of 923 patients at high/very high CVD risk were included in our analysis. Overall, a high TMAO level was associated with both major adverse cardiovascular events (RR = 2.05; 95% CI 1.61-2.61) and all-cause mortality (RR = 3.42; 95% CI 2.27-5.15).

Our findings support a role of high TMAO levels in predicting CVD events. High levels of TMAO may be a new CVD risk factor, potentially useful to better plan personalized CVD prevention strategies.