Association Between Triglyceride-Glucose Index and 28-Day Mortality in Patients with Sepsis and Heart Failure: A Retrospective Study Using the MIMIC-IV Database.

Background The triglyceride-glucose body mass index (TyG-BMI) is a surrogate marker for insulin resistance and has been identified as a predictor of cardiovascular diseases. However, its role in patients with sepsis and heart failure remains unclear. This study aims to explore the association between the TyG-BMI index and 28-day mortality in patients with sepsis and heart failure. Methods This retrospective observational cohort study used data from the Medical Information Mart for Intensive Care (MIMIC-IV) database. We identified patients with sepsis and heart failure and divided them into tertiles based on their TyG-BMI levels. The primary outcome was 28-day mortality, while secondary outcomes included 1-year mortality, in-hospital mortality, and ICU mortality. Cox proportional hazards regression and restricted cubic spline analysis were used to examine the association between TyG-BMI index and clinical outcomes in critically ill patients. Survival curves were estimated using the Kaplan-Meier (K-M) method, and subgroup analyses were performed. Results A total of 598 patients were included in this study, of whom 60.6% were male. The observed mortality rates were 35.7% at 28 days, 51.3% at 1 year, 28.1% in the ICU, and 34.5% in-hospital. Multivariable Cox proportional hazards analysis showed that patients in the lowest TyG-BMI tertile had a significantly higher risk of all-cause mortality. Compared to the lowest TyG-BMI group, the fully adjusted Cox model revealed hazard ratios (HRs) for 28-day, 1-year, ICU, and in-hospital mortality of 0.651 (95% CI: 0.468–0.904, p = 0.011), 0.597 (95% CI: 0.417–0.853, p = 0.004), 0.634 (95% CI: 0.455–0.883, p = 0.007), and 0.603 (95% CI: 0.457–0.797, p < 0.001), respectively. Kaplan-Meier analysis showed that higher TyG-BMI levels were associated with significantly lower all-cause mortality for 28-day, 1-year, ICU, and in-hospital outcomes (log-rank p = 0.02, p = 0.00087, p = 0.016, p = 0.019, respectively). Additionally, restricted cubic spline analysis indicated that lower TyG-BMI levels were associated with a gradual increase in all-cause mortality risk. Conclusion The TyG-BMI index is significantly associated with 28-day, 1-year, in-hospital, and ICU all-cause mortality in patients with sepsis and heart failure. Higher TyG-BMI levels are linked to a reduced risk of mortality, suggesting that the TyG-BMI index may be useful for identifying high-risk patients with sepsis and heart failure.