The C-reactive protein-triglyceride-glucose index (CTI) as a predictor of mortality and hospital stay in critically ill patients: a retrospective cohort study.

Background: Population aging has increased the demand for intensive care, with critically ill patients facing high mortality and prolonged hospital stays. New biomarkers are needed to predict outcomes early. The C-reactive protein-triglyceride-glucose index (CTI) integrates insulin resistance and inflammation, but its Link to outcomes in critically ill patients is unknown. This study aims to investigate the association between CTI and 30-day and 365-day all-cause mortality and length of hospital stay in critically ill patients.

Methods: This retrospective study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, including 2,428 ICU patients admitted from 2008 to 2022. The primary outcomes were 30-day and 365-day all-cause mortality, while secondary outcomes included length of hospital stay and ICU stay. CTI was calculated based on biochemical data (CRP, triglycerides, and glucose). Kaplan-Meier survival analysis, Cox regression models, and mediation analysis were employed to assess the relationship between CTI and clinical outcomes.

Results: Higher CTI levels were associated with increased all-cause mortality at both 30 days (HR: 1.81, 95% CI: 1.31-2.52, P < 0.001 for the highest quartile) and 365 days (HR: 1.80, 95% CI: 1.43-2.28, P < 0.001 for the highest quartile). CTI exhibited a Linear relationship with mortality, with each unit increase in CTI corresponding to a 25% increase in 30-day mortality and a 26% increase in 365-day mortality. Nutritional risk, assessed by the Geriatric Nutritional Risk Index (GNRI) levels, significantly mediated the association between CTI and mortality, with a stronger effect observed in long-term outcomes. Furthermore, CTI outperformed the triglyceride-glucose (TyG) index and C-reactive protein (CRP) in predicting mortality, and the results remained consistent after adjusting for baseline severity scores. Additionally, higher CTI levels were associated with longer hospital and ICU stays (β = 0.44 days and β = 0.22 days, respectively, P < 0.001).

Conclusions: CTI is a robust predictor of mortality and hospital stay duration in critically ill patients, integrating the effects of insulin resistance and inflammation. Nutritional risk plays a significant mediating role in the association between CTI and mortality, particularly in long-term outcomes. CTI may serve as a valuable tool for early risk stratification and clinical decision-making in the ICU setting.