Rebnord EW, et al. - The associations of the plasma and urine kynurenine:tryptophan ratio (KTR) to incident type 2 diabetes were assessed in this study. In individuals with coronary artery disease (CAD), urine KTR was a strong predictor of incident type 2 diabetes. Potential clinical implications and possible pathogenic roles of renal kynurenine excretion in type 2 diabetes development needed to be further explained.

• For this study, the authors followed 2519 individuals with coronary artery disease (CAD; 73.1% men) without diabetes at baseline for a median of 7.6 years, during which 173 (6.9%) new incidences of type 2 diabetes were identified.
• They applied multivariate Cox regression analyses to examine the prospective relationships of plasma and urine KTR with new onset type 2 diabetes.

• Mean (SD) age was 61.3 (10.4) years, BMI was 25.9 (3.71) kg/m² and median (interquartile range) HbA_1c was 5.6% (5.0%-6.0%) (38 [31-42] mmol/mol) at inclusion.
• Plasma KTR was not significantly associated with type 2 diabetes risk.
• On the other hand, urine KTR demonstrated a strong positive association.
• In the age- and sex-adjusted and multivariate models, the HRs (95% CIs) were 2.59 (1.56, 4.30) and 2.35 (1.39, 3.96), respectively, comparing quartile 4 with quartile 1.