U-shaped relationship between uric acid to albumin ratio and 3-month outcome in patients with acute ischemic stroke: a retrospective cohort study

The prognostic value of the uric acid to albumin ratio (UAR) in acute ischemic stroke (AIS) remains unclear. This study aimed to assess the predictive ability of UAR for 3-month prognosis in AIS patients and to investigate the dose-response relationship between UAR and 3-month prognosis. This retrospective cohort study included 4,812 patients hospitalized for AIS from December 2010 to May 2022. Restricted cubic spline (RCS) and locally weighted scatterplot smoothing (LOESS) analyses were used to explore the non-linear relationship between UAR and 3-month prognosis, and potential inflection points were identified using threshold effects analysis. Potential confounders were identified using L1-regularized LASSO regression with 10-fold cross-validation. Subsequently, multivariate logistic regression models (crude, minimally adjusted, and fully adjusted) were employed to assess the association between UAR and 3-month prognosis. A total of 4,812 AIS patients (mean age 61.48 ± 12.20 years, 71.16% male) were included in this study. RCS and LOESS analyses revealed a U-shaped nonlinear relationship between UAR and 3-month prognosis, with an inflection point at 1.60. In the fully adjusted model, higher UAR was significantly associated with reduced odds of poor functional outcome (OR = 0.71, 95% CI 0.60–0.84; P < 0.001). Stratified analysis showed that for UAR < 1.60, each unit increase was associated with a 66% reduction in the odds of poor prognosis (OR = 0.34, 95% CI 0.26–0.46; P < 0.001), whereas no significant association was observed for UAR ≥ 1.60 (OR = 1.27, 95% CI 0.94–1.73; P = 0.116). In the UAR < 1.6 stratum, subgroup analyses demonstrated a consistent protective association in non-CKD patients (OR = 0.35, 95% CI 0.26–0.47), whereas the result in CKD patients was not significant (OR = 0.33, 95% CI 0.04–2.62). There is a U-shaped relationship between UAR and 3-month modified Rankin Scale (mRS) score outcomes in AIS patients. Specifically, UAR levels below a threshold of 1.60 were associated with favorable 3-month prognosis, although this association was not statistically significant above this threshold after full adjustment. Therefore, UAR may serve as a potential predictor of AIS prognosis.