Nonlinear relationship between blood urea nitrogen to albumin ratio and 3-month outcomes in patients with acute ischemic stroke: a second analysis based on a prospective cohort study

World Neurosurg. 2024 Nov 20:S1878-8750(24)01895-3. doi: 10.1016/j.wneu.2024.11.035. Online ahead of print.

Abstract

Objective: Patients with acute ischemic stroke (AIS) have limited evidence regarding the relationship between blood urea nitrogen and albumin (BUN/ALB). Aiming to investigate the relationship between the BUN/ALB ratio and poor outcomes in AIS patients at 3-months was the purpose of this study.

Methods: AIS participants at a Korean hospital from January 2010 to December 2016 were included in a secondary analysis of a prospective cohort study. Logistic regression and restricted cubic splines were used to examine the relationship between BUN/ALB ratio and poor outcomes after 3 months.

Results: There is a skewed distribution of BUN/ALB ratios, ranging from 0.114 to 1.250. Model II of the binary logistic regression showed that the BUN/ALB ratio was not statistically significant in predicting poor outcomes for AIS patients after three months. However, there was a notable nonlinear relationship between them, with the inflection point of the BUN/ALB ratio identified as 0.326. The BUN/ALB ratio on the left side of the inflection point was associated with a 42% reduction in 3-month poor outcomes (OR=0.58, 95% CI: 0.40 to 0.83). Conversely, the relationship was not statistically significant on the right side of the inflection point.

Conclusion: The BUN/ALB ratio and poor outcomes in AIS patients show a nonlinear correlation. For AIS patients, a BUN/ALB ratio of approximately 0.326 is associated with the lowest risk of adverse outcomes at 3 months. Specifically, for non-smoking AIS patients, a BUN/ALB ratio of approximately 0.295 is associated with the lowest risk of adverse outcomes at 3 months.

Keywords: 3-month poor outcomes; Acute ischemic stroke; Blood urea nitrogen to albumin ratio; Nonlinear relationship; Smooth curve fitting.