Insulin Resistance-Nutritional Index: A Simple Index and Potential Predictor of Mortality Risk in Patients with Chronic Heart Failure and Type 2 Diabetes.

Background: Patients with chronic heart failure (CHF) and type 2 diabetes mellitus (DM) are prone to insulin resistance and malnutrition, both of which are significant prognostic factors for CHF. However, the combined effect of the triglyceride-glucose index (TyG index) and prognostic nutritional index (PNI) on the mortality risk in patients with CHF and type 2 DM has not yet been studied.

Methods: We enrolled 3,315 patients with CHF and type 2 DM. We used a multivariate Cox regression model to assess hazard ratios (HRs) with 95% confidence intervals (CIs) for mortality risk based on TyG index and PNI levels. Furthermore, we constructed a novel index, the insulin resistance-nutritional index (IRNI), defined as TyG index/Ln (PNI), and evaluated its prognostic significance.

Results: During follow-up, 1,214 deaths occurred. Participants with a high TyG index and non-high PNI had a significantly higher mortality risk compared to those with a non-high TyG index and high PNI, with an adjusted HR of 1.91 (95% CI, 1.57-2.32). The multivariate Cox regression analysis revealed HRs for all-cause and cardiovascular deaths of 1.93 (95% CI, 1.66-2.26; P < 0.001) and 2.50 (95% CI, 2.05-3.06; P < 0.001), respectively, when comparing the highest and lowest IRNI tertiles. IRNI's predictive power was stronger in groups with higher adapted Diabetes Complications Severity Index scores (P for interaction < 0.05). Additionally, adding IRNI to the baseline risk model significantly improved predictive performance, showing a greater effect compared to the TyG index or PNI.

Conclusion: IRNI, a novel and composite index reflecting insulin resistance and nutritional status, emerges as a potentially valuable prognostic marker for patients with CHF and type 2 DM.