U-shaped association between serum uric acid at admission and post-stroke epilepsy in patients with ischemic stroke: a cohort study

Background: The relationship between serum uric acid (SUA) and post-stroke epilepsy (PSE) remains uncertain. We investigated the association between serum uric acid at admission and PSE after acute ischemic stroke. Methods: A retrospective cohort study was conducted on 21,459 ischemic stroke patients. Serum uric acid at admission was measured as part of routine laboratory testing and analyzed in quartiles (Q1-Q4). Logistic regression models with restricted cubic splines (RCS) were used to investigate the potential nonlinearity of the association between serum uric acid (SUA) levels and the risk of post-stroke epilepsy (PSE), with adjustments for demographic, clinical, and laboratory variables. Propensity score matching (PSM) was additionally employed to address potential confounding. Results: A U-shaped association was observed. Compared with the mid-range (Q2-Q3: ~305.3-373.9 μmol/L), both low (Q1) and high (Q4) SUA were associated with higher PSE risk (adjusted OR 2.32, 95% CI 1.79-2.99; and 1.60, 95% CI 1.26-2.02). RCS identified an inflection point around 335 μmol/L: below this level, higher SUA related to lower PSE risk, whereas above it, higher SUA related to higher risk. Findings were robust in propensity score-based and sensitivity analyses. Conclusion: SUA shows a U-shaped association with PSE after ischemic stroke. SUA levels within an intermediate range were associated with a lower risk of PSE. This observation is hypothesis-generating and requires confirmation in prospective studies to evaluate potential causal relationships.