Association between Blood Urea Nitrogen-to-creatinine Ratio and Three-Month Outcome in Patients with Acute Ischemic Stroke

Background: Hydration status significantly affects the clinical outcome of acute ischemic stroke (AIS) patients. Blood urea nitrogen-to-creatinine ratio (BUN/Cr) is a biomarker of hydration status. However, it is not known whether there is a relationship between BUN/Cr and three-month outcome as assessed by the modified Rankin Scale (mRS) score in AIS patients. Methods: AIS patients admitted to West China Hospital from 2012 to 2016 were prospectively and consecutively enrolled and baseline data were collected. Poor clinical outcome was defined as three-month mRS > 2. Univariate and multivariate logistic regression analyses were performed to determine the relationship between BUN/Cr and three-month outcome. Confounding factors were identified by univariate analysis. Stratified logistic regression analysis was performed to identify effect modifiers. Results: A total of 1738 patients were included in the study. BUN/Cr showed a positive correlation with the three-month outcome (OR 1.02, 95% CI 1.00-1.03, p=0.04). However, after adjusting for potential confounders, the correlation was no longer significant (p=0.95). An interaction between BUN/Cr and high-density lipoprotein (HDL) was discovered (p=0.03), with a significant correlation between BUN/Cr and three-month outcome in patients with higher HDL (OR 1.03, 95% CI 1.00-1.07, p=0.04). Conclusion: Elevated BUN/Cr is associated with poor three-month outcome in AIS patients with high HDL levels.