Lower admission reverse shock index multiplied by Glasgow coma scale score is associated with early hematoma expansion in spontaneous intracerebral hemorrhage.

BACKGROUND: Early hematoma expansion (HE) contributes to neurological deterioration after spontaneous intracerebral hemorrhage (sICH), but simple bedside tools for early risk stratification remain limited. This study examined the association between the reverse shock index multiplied by Glasgow Coma Scale score (rSIG) and early HE and evaluated its predictive performance. METHODS: Consecutive adults with sICH admitted to a single center between July 2016 and June 2026 were retrospectively included. rSIG was calculated as Glasgow Coma Scale score × systolic blood pressure/heart rate using first admission measurements. HE was defined as an absolute hematoma-volume increase >6 mL or a relative increase >33% on follow-up non-contrast computed tomography within 8 h. Associations were assessed using hierarchical logistic regression, restricted cubic splines, quartile analysis, bootstrap resampling, and 1:2 matched sensitivity analysis. RESULTS: Of 2,450 patients screened, 2,035 were included, and 156 (7.7%) developed early HE. Each 5-point decrease in rSIG was independently associated with higher odds of HE in the fully adjusted model (adjusted odds ratio, 1.783; 95% confidence interval, 1.560-2.038; p < 0.001). The association was nonlinear and most pronounced at low rSIG values (P for nonlinearity <0.001). The rSIG-only model yielded an area under the curve of 0.828 (95% confidence interval, 0.789-0.864). The optimal cutoff was 17.44, with 78.2% sensitivity and 80.2% specificity. Calibration was acceptable, and decision curve analysis indicated net benefit across threshold probabilities of approximately 1.7-30%. Findings remained consistent in bootstrap and matched analyses. CONCLUSION: Lower admission rSIG was independently and nonlinearly associated with early HE after sICH. rSIG may provide a rapid bedside aid for early risk stratification and complement imaging assessment, although prospective.