Short-term survival in critically ill ischemic stroke patients: insights into triglyceride-glucose systemic immune-inflammation index from the MIMIC-IV database

Background and Purpose : Ischemic stroke (IS) is a leading cause of mortality and disability worldwide. Inflammatory and metabolic markers play crucial roles in stroke pathophysiology and outcomes. This study aimed to investigate the relationship between triglyceride-glucose systemic immune-inflammation (TYG-SII) index and short-term mortality in critically ill patients with IS. Methods : This study identified patients with severe IS requiring ICU admission from the Medical Information Mart for Intensive Care (MIMIC-IV) database, and divided them into quartiles based on TYG-SII values. Patients with stroke were identified and the TyG-SII index was calculated as ln[(ln[TG (mg/dL) × FBG (mg/dL)/2] × platelet count (PLT, 10⁹/L) × neutrophil count (NEU, 10⁹/L)/lymphocyte count (LYM, 10⁹/L))]. The outcomes included 30-day and 90-day all-cause mortality (short-term survival). Kaplan-Meier survival analysis, Cox proportional hazards models, restricted cubic spline regression, and subgroup analyses were performed to evaluate the association between TYG-SII and mortality risk. The predictive value of TYG-SII was assessed using ROC curves and multivariable logistic regression. Results : A total of 692 patients (50.9% male) were enrolled. Subsequently, we stratified the subjects into quartiles, relying on their TyG-SII index. Higher TYG-SII levels were significantly associated with increased mortality at 30 days and 90 days (both p<0.001). Multivariate Cox regression analysis results manifested that heightened TyG-SII was significantly related to ACM at 30 days (adjusted hazard ratio [aHR]: 6.14; 95% confidence interval [CI]: 3.19-11.79, p=0.001), 90 days (aHR: 5.33; 95% CI: 2.96-3.47, p=0.001). The results of RCS analysis demonstrated a progressive elevation in ACM risk with rising TyG-SII levels (p for non-linearity <0.001). In subgroup analyses, the association between TYG-SII and mortality remained consistent across age and sex categories. ROC curve analysis demonstrated that TYG-SII (AUC=0.728 for 30-day mortality; AUC=0.716 for 90-day mortality) had superior predictive value compared to TYG or SII alone. Multivariable logistic regression confirmed TYG-SII as an independent risk factor for short-term mortality after adjusting for thrombolysis, systolic blood pressure, SOFA score, and white blood cell count. Conclusions : TYG-SII is a novel and promising prognostic marker for predicting short-term mortality in in critically ill patients with IS. The integration of inflammatory and metabolic indices may provide a more comprehensive assessment of stroke outcomes and help identify high-risk patients who might benefit from more intensive monitoring and intervention.