Bacterial metabolites trimethylamine N-oxide and butyrate as surrogates of small intestinal bacterial overgrowth in patients with a recent decompensated heart failure

In patients with heart failure (HF), the exhaled concentrations of hydrogen after a breath test—a non-invasive assessment of small intestinal overgrowth- has been related to HF severity and higher risk of adverse outcomes. Indeed, two intestinal bacterial metabolites—blood Trimethylamine N-Oxide (TMAO) and butyrate—have been related to a worse prognosis in HF. However, the relationship between the exhaled concentrations of hydrogen after a breath test and these two metabolites remains unknown. Thus, in this post-hoc analysis, we sought to evaluate whether these two metabolites are associated with the exhaled concentrations of hydrogen after a breath test in patients with a recent admission for HF. We included 60 patients with a recent hospitalization for HF. Cumulative hydrogen over time was integrated into a single measurement by the area under the concentration curve (AUC-H2). A linear regression multivariable analysis was used to evaluate the associations. A 2-sided p-value < 0.05 was considered to be statistically significant. The median (p25–p75) amino-terminal pro-brain natriuretic peptide, AUC-H2, TMAO, and Butyrate were 4789 pg/ml (1956–11149), 1615 (700–2585), 0.68 (0.42–1.12), and 0.22 ± 13, respectively. After multivariate adjustment, TMAO and butyrate were significantly associated with AUC-H2 (p = 0.027 and p = 0.009, respectively). For TMAO, this association was positive and for butyrate, negative. Bacterial-origin metabolites TMAO and Butyrate were independently related to AUC-H2 in patients with a recent hospitalization for acute HF.