Serum uric acid levels and outcome during admission in acute ischaemic stroke, depending on renal function

Background: The relationship between serum uric acid (SUA) levels and stroke is controversial. The discrepancies in the results could be due to the uneven setting of comorbidity. It is known that hyperuricaemia increases in parallel with the decline in renal function; however, there are few studies that adjust for renal disease.

Aim: To investigate the relationship between SUA levels in the acute phase of ischaemic stroke according to the presence or absence of chronic kidney disease and clinical outcomes during admission.

Methods: Retrospective cross-sectional analysis of patients recruited through a unicentric stroke registry. The sample was divided according to its quartiles of SUA. Renal disease was defined based on the haematocrit, urea and Gender (HUGE) formula. The outcome was determined by the National Institutes of Health Stroke Scale (NIHSS) score. Statistically robust methods were used with R (version 3.3.2).

Results: A total of 412 patients (53.8% male) were analysed. The NIHSS score decreased as the SUA levels increased (p < 0.0009). Robust linear regression analysis showed a significant association between quantitative SUA levels and NIHSS score (p < 0.0003), even when patients were categorized according to renal function (p < 0.05). In an adjusted multivariate model, SUA levels showed an independent protective effect on the severity of stroke (OR = 0.67, 95% CI 0.51–0.88, p = 0.004).

Conclusions: Our results support the hypothesis that hyperuricaemia plays a protective role in the prognosis of stroke, independently from renal function, and that even in patients with chronic kidney disease, it remains as a protective agent.