# Kynurenine as a Predictor of Long-Term Mortality: A 10-Year Follow-Up from the KORONEF Registry

## TL;DR

High levels of kynurenine are linked to increased long-term mortality in patients with heart and kidney conditions.

## Contribution

This study shows that kynurenine is an independent predictor of 10-year mortality beyond traditional risk factors.

## Key findings

- Mortality rates increased with higher kynurenine tertiles (17.6%, 28.2%, 42.9%).
- Kynurenine independently predicted mortality in multivariable analysis (HR: 1.79).
- Other kynurenine pathway metabolites were not associated with mortality.

## Abstract

Background: The kynurenine (KYN) pathway of tryptophan metabolism has been linked to inflammation and cardiovascular risk, but its long-term prognostic value remains unclear. Methods: We analyzed 492 patients from the KORONEF registry who underwent coronary and renal angiography and were followed for a median of 10.2 years. Plasma levels of tryptophan (TRP), KYN, and downstream metabolites were measured. The primary endpoint was all-cause mortality. Results: The mean age was 64.4 ± 9.9 years, and 37.2% of patients were female. Common comorbidities included hypertension (74.8%), dyslipidemia (46.0%), and diabetes (25.8%). Overall mortality reached 29.5% and increased across KYN tertiles: 17.6% (T1), 28.2% (T2), and 42.9% (T3) (p < 0.001). In a multivariable Cox analysis, KYN independently predicted mortality (HR: 1.79; 95% CI: 1.15–2.44; p < 0.001), alongside age, diabetes, prior myocardial infarction, chronic kidney disease, and left ventricular ejection fraction. Other kynurenine pathway metabolites were not independently associated with outcomes. Conclusions: Elevated kynurenine levels independently predict 10-year all-cause mortality in patients undergoing coronary angiography. KYN may represent a useful prognostic biomarker beyond traditional clinical and angiographic variables.