Triglyceride-glucose index and 28-day all-cause mortality in critically ill obese patients: A MIMIC-IV database analysis.

Background: The triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance, has been linked to various metabolic disorders. This study aimed to investigate the association between the TyG index and 28-day all-cause mortality in obese critically ill patients.

Methods: This study utilized the Medical Information Mart for Intensive Care IV (MIMIC-IV) database and included adult patients with body mass index ≥30 kg/m² admitted to the intensive care unit (ICU) for the first time. The TyG index was calculated as ln[fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. The relationship between the TyG index and 28-day all-cause mortality was evaluated using Cox proportional hazards models, and restricted cubic splines (RCS) were employed to explore the dose-response relationship. Subgroup analyses were used to confirm the robustness of the results.

Results: During a mean ICU stay of 7.22 days, 291 patients (22.79%) experienced 28-day all-cause mortality. Kaplan-Meier analysis revealed a significantly increased mortality risk with higher TyG index quartiles (log-rank P < .001). Multivariable Cox regression showed that each 1-unit increase in the TyG index was associated with a 41% higher mortality risk (hazard ratio [HR] = 1.41, 95% CI: 1.21-1.63). Patients in quartile 4 had a 98% higher risk compared to quartile 1 (HR = 1.98, 95% CI: 1.30-3.02). RCS analysis showed that higher levels of TyG index (>9.25) were associated with an increased risk of 28-day all-cause mortality. Subgroup analyses confirmed consistent associations across age, sex, and comorbidity subgroups.

Conclusions: The TyG index is significantly associated with 28-day all-cause mortality in obese critically ill patients. A higher TyG index serves as an independent predictor of short-term mortality risk in this population.