The Effects of Statin Therapy on Circulating Levels of Trimethylamine N-oxide: A Systematic Review and Meta-analysis

Abstract

Background Gut microbiota is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD) through the metabolites, which can induce atherogenesis. One of these metabolites is trimethylamine N-oxide (TMAO). Some studies indicate that statins do not only decrease LDL-cholesterol and thus ASCVD risk, but they also affect gut microbiota. There are only a few studies on humans suggesting that statins might also decrease TMAO, but their results are not unanimous. This meta-analysis aimed to provide an answer as to whether statins do affect decreasing the plasma levels of atherogenic TMAO. Methods A systematic literature search in PubMed, Scopus, Embase, and Web of Science was performed from inception to January 1st, 2023. To assess the quality of each study included in the meta-analysis, the Cochrane Quality Assessment tool 1 (ROB 1) was used. Comprehensive Meta-Analysis V3 software was used to perform the meta-analysis. The weighted mean difference was also used. A random effects meta-analysis was used to calculate the overall estimate of effect size. In the leave-one-out approach, one study was excluded from each analysis to evaluate the effect of each study on the overall effect size. Results Random-effects meta-analysis of 3 studies including 244 patients demonstrated a significant decrease in plasma TMAO levels after statin treatment (WMD: -1.839, 95% CI: -2.391, -1.287, p<0.001; I2 :0). The reduction in TMAO was robust in the leaveone-out sensitivity analysis. Conclusion Statins might reduce TMAO levels, but there is a need for further evidence from long-term studies taking into account different types and doses of statins.