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.

Objective: Patients with acute ischemic stroke (AIS) have limited evidence regarding the relationship between blood urea nitrogen and albumin. Aiming to investigate the relationship between the blood urea nitrogen to albumin ratio (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 3 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 (odds ratio = 0.58, 95% confidence interval: 0.40 to 0.83). Conversely, the relationship was not statistically significant on the right side of the inflection point.

Conclusions: 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 nonsmoking AIS patients, a BUN/ALB ratio of approximately 0.295 is associated with the lowest risk of adverse outcomes at 3 months.