Effect of renal function on association between uric acid and prognosis in acute ischemic stroke patients with elevated systolic blood pressure

Background and aims: The prognostic value of uric acid in ischemic stroke remains controversial, and it is unclear whether renal function status modifies the prognostic value of uric acid in ischemic stroke patients.

Methods: A total of 3284 acute ischemic stroke patients from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS) with creatinine and uric acid measurements were included in this analysis. The primary outcome was a composite of death and major disability (modified Rankin Scale score ≥3) at 1 year after stroke.

Results: The prognostic value of uric acid in ischemic stroke was appreciably modified by patients' renal function status (p for interaction <0.05). After multivariate adjustment, higher uric acid level was significantly associated with a better prognosis in patients with normal renal function (odds ratio, 0.61; 95% confidence interval, 0.45-0.83), but not in those with abnormal renal function (odds ratio, 0.87; 95% confidence interval, 0.48-1.55), when two extreme quartiles were compared. Linear association between uric acid and primary outcome was observed among patients with normal renal function (p for linearity = 0.023).

Conclusion: The present study suggests that high serum uric acid concentration is associated with better prognosis in ischemic stroke patients with normal renal function, but not in those with abnormal renal function. The establishment of causality between increased uric acid levels and better stroke prognosis needs more suitably designed randomized clinical trials.

Keywords: Uric acid; ischemic stroke; renal function.