Association Between the C-Reactive Protein–Triglyceride Glucose Index and All- Cause Mortality in Critically Ill Patients with Acute Ischemic Stroke: A Retrospective Cohort Study

Abstract Objective To investigate the association between the C-reactive protein-triglyceride-glucose index (CTI) and all-cause mortality in critically ill ischemic stroke patients, and to evaluate its prognostic value. Methods A retrospective cohort analysis was conducted comprising 476 critically ill patients with a confirmed diagnosis of ischemic stroke, drawing upon data extracted from the MIMIC-IV database covering the period 2008–2022.The CTI was calculated using the formula: \(\:0.412\times\:\:Ln\:\left(CRP\:\right[mg/L\left]\right)\:+\:Ln\:\left(TG\:\right[mg/dl]\:\times\:\:FPG\:[mg/dl\left]\right)/2.\) The principal endpoint was all-cause mortality at 3 months, with mortality at 1 year designated as the secondary outcome. Cox proportional hazards regression, restricted cubic spline modeling, and stratified subgroup analyses were applied to examine the link between CTI and mortality. The predictive capacity of the CTI was compared with that of the conventional TyG index through receiver operating characteristic (ROC) curve analysis. Results The median CTI was 6.1 (IQR: 5.4–6.8). Mortality rates at 3 months and 1 year were 21% and 28%, respectively. Following multivariable adjustment, each 1-unit increment in CTI corresponded to a 37% elevated risk of 3-month mortality (hazard ratio [HR] 1.37, 95% confidence interval [CI] 1.06–1.78; P = 0.017). Relative to the lowest CTI tertile, the highest tertile conferred an 84% elevated risk of 3-month mortality (HR 1.84, 95% CI 1.07–3.17; P = 0.027).Restricted cubic spline analysis indicated a linear relationship between CTI and mortality (P for nonlinearity > 0.05). Subgroup analysis revealed that the association between CTI and 3-month mortality was stronger in patients with sepsis (P for interaction < 0.05). The predictive performance of CTI for 3-month (AUC = 0.627) and 1-year (AUC = 0.644) mortality was significantly superior to that of the TyG index (AUC = 0.563 and 0.546, respectively; P < 0.05). Conclusion The CTI serves as an independent predictor of both 3-month all-cause mortality and 1-year mortality in critically ill ischemic stroke patients. It exhibits superior prognostic discrimination relative to the conventional TyG index, indicating potential utility as an accessible instrument for clinical risk stratification and personalized therapeutic management.