Association with outcomes and response to treatment of trimethylamine N-oxide in heart failure: results from BIOSTAT-CHF

Aims Association of elevated circulating levels of trimethylamine N-oxide (TMAO) with adverse outcomes in patients with heart failure (HF) has been described. However, response of TMAO levels to treatment and medications has not been investigated. Therefore, we investigated whether TMAO levels are responsive to guideline-recommended treatment and medications, and further reflect changes in outcomes. Methods and results TMAO levels were investigated in the systems BIOlogy Study to TAilored Treatment in Chronic Heart Failure (BIOSTAT-CHF), which addressed response to guideline-recommended pharmacological treatment. TMAO levels in 2234 patients with new-onset or progressively worsening HF showed strong associations with adverse events (mortality and/or rehospitalisation) at 1, 2 and 3 years [hazard ratio (HR) 1.37-1.51, P Conclusion TMAO levels were associated with adverse outcomes (mortality and/or rehospitalisation) in BIOSTAT-CHF, and did not respond to guideline-based pharmacological treatment in contrast to BNP levels which did as expected. Lower TMAO levels were associated with favourable outcome regardless of treatment