Association between blood urea nitrogen to creatinine ratio and 3-month outcome in patients with acute ischaemic stroke: a retrospective cohort study from a large healthcare system

Abstract

Objectives The blood urea nitrogen to creatinine (BUN/Cr) ratio is associated with early neurological deterioration in acute ischaemic stroke (AIS). However, the predictive value of the BUN/Cr ratio for the AIS prognosis remains unclear. Therefore, we evaluated the correlation between the BUN/Cr ratio and the 3-month outcome in patients with AIS, further testing their dose–response relationship.Design This retrospective cohort study enrolled patients with AIS who were admitted between 1 January 2013 and 31 May 2022. Poor clinical outcome was defined as 3-month Modified Rankin Scale (mRS) >2. Cox proportional HR was used to evaluate the correlation between the BUN/Cr ratio and 3-month outcome. Restricted cubic spline and robust locally weighted regression analyses were conducted to determine the dose–response relationship between the BUN/Cr ratio and the 3-month outcome.Results A total of 4952 eligible patients were included in the study. The patients were divided into three groups according to the tertiles of BUN/Cr ratio (T1, <0.071; T2, 0.071–0.093; and T3, >0.093). After logistic regression adjustment for demographic and clinical characteristics, the BUN/Cr ratio was found to be independently associated with the 3-month outcome in patients with AIS. The restricted cubic spline and locally regression smoothing scatterplot graph showed a strong dose–response relationship between the BUN/Cr ratio and the 3-month outcome in patients with AIS.Conclusion A dose–response relationship was observed between the BUN/Cr ratio and the 3-month outcome in patients with AIS, suggesting that the BUN/Cr ratio could serve as a reliable predictor for the AIS prognosis.