TMAO levels predict mortality in patients at nutritional risk

Patients at risk of malnutrition with elevated baseline levels of trimethylamine N-oxide (TMAO) are at increased risk of mortality over 6 months, according to a study.

Overall, 218 patients had available TMAO measurements for analysis. Individuals in the highest quartiles of TMAO concentration were at significantly higher risk of all-cause mortality than those in the lowest quartile after 180 days (adjusted hazard ratio [aHR], 1.92, 95 percent confidence interval [CI], 1.03‒3.56; p=0.04) and 5 years (aHR, 2.01, 95 percent CI, 1.23‒3.31; p=0.006).

This trend persisted for major adverse cardiovascular events (MACE). On the other hand, no significant associations were observed between dietary factors or nutritional history and admission TMAO levels. Likewise, TMAO was not predictive of the response to nutritional therapy.

“Additional research is needed to determine if dietary interventions can successfully modulate TMAO levels and, in turn, improve clinical outcomes,” the authors said.

A secondary analysis was performed on the randomized controlled EFFORT trial, which compared individualized nutritional therapy with usual care in medical inpatients at nutritional risk. The authors explored the association of TMAO concentrations at admission with all-cause mortality after 180 days (primary endpoint) and MACE using quartile-based regression analysis.

“TMAO, a metabolite produced by the gut microbiota, is highly influenced by dietary factors and is linked to negative health outcomes including all-cause mortality and cardiovascular events,” the authors said.