Serum Bilirubin as a Severity and Prognostic Indicator in Acute Ischemic Stroke a Tertiary Care Hospital-Based I-Year Observational Study

Background: Acute Ischemic Stroke (AIS) remains a leading cause of morbidity and mortality. Identifying simple biochemical markers that predict severity and outcomes may improve early risk stratification. Serum bilirubin, despite its antioxidant properties, has shown conflicting associations with AIS outcomes.

Aim: To evaluate the role of serum bilirubin (total, direct, and indirect) as a severity and prognostic indicator in AIS.

Methods: A prospective observational study was conducted over one year at a tertiary care centre in Tamil Nadu, including 96 newly diagnosed AIS patients. Serum bilirubin levels were measured at admission, while stroke severity and functional outcomes were assessed using the NIHSS and mRS, respectively. Correlation analysis, ROC curve analysis, and multivariate logistic regression were performed to determine the predictive value of bilirubin.

Results: Total, direct, and indirect bilirubin showed significant positive correlations with NIHSS (r = 0.482, 0.461, 0.291; p < 0.01) and mRS scores (r = 0.551, 0.544, 0.324; p < 0.01). Total bilirubin demonstrated the highest predictive accuracy for severe mRS outcomes (AUC = 0.798), with an optimal cutoff of ≥2 mg/dL. Multivariate analysis identified total bilirubin <2 mg/dL as an independent predictor of better outcomes (Adjusted OR = 9; p = 0.012).

Conclusion: Elevated serum bilirubin, particularly total bilirubin ≥2 mg/dL, is strongly associated with increased stroke severity and poorer functional outcomes in AIS. As a simple and routinely available biomarker, serum bilirubin can support early risk stratification and clinical decision-making.