Prognostic value of gut microbe‐generated metabolite phenylacetylglutamine in patients with heart failure.

Aim: Phenylacetylglutamine (PAGln) is a phenylalanine‐derived metabolite produced by gut microbiota with mechanistic links to heart failure (HF)‐relevant phenotypes. We sought to investigate the prognostic value of PAGln in patients with stable HF. Methods and results: Fasting plasma PAGln levels were measured by stable‐isotope‐dilution liquid chromatography–tandem mass spectrometry (LC‐MS/MS) in patients with stable HF from two large cohorts. All‐cause mortality was assessed at 5‐year follow‐up in the Cleveland cohort, and HF, hospitalization, or mortality were assessed at 3‐year follow‐up in the Berlin cohort. Within the Cleveland cohort, median PAGln levels were 4.2 (interquartile range [IQR] 2.4–6.9) μM. Highest quartile of PAGln was associated with 3.09‐fold increased mortality risk compared to lowest quartile. Following adjustments for traditional risk factors, as well as race, estimated glomerular filtration rate, amino‐terminal pro‐B‐type natriuretic peptide, high‐sensitivity C‐reactive protein, left ventricular ejection fraction, ischaemic aetiology, and HF drug treatment, elevated PAGln levels remained predictive of 5‐year mortality in quartile comparisons (adjusted hazard ratio [HR] [95% confidence interval, CI] for Q4 vs Q1: 1.64 [1.07–2.53]). In the Berlin cohort, a similar distribution of PAGln levels was observed (median 3.2 [IQR 2.0–4.8] μM), and PAGln levels were associated with a 1.92‐fold increase in 3‐year HF hospitalization or all‐cause mortality risk (adjusted HR [95% CI] for Q4 vs Q1: 1.92 [1.02‐3.61]). Prognostic value of PAGln appears to be independent of trimethylamine N‐oxide levels. Conclusion: High levels of PAGln are associated with adverse outcomes independent of traditional cardiac risk factors and cardio‐renal risk markers. [ABSTRACT FROM AUTHOR]