Hyperuricemia is associated with decreased renal function and occurrence of end-stage renal disease in patients with microscopic polyangiitis and granulomatosis with polyangiitis: a retrospective study.

Current evidence suggests that high uric acid levels are associated with accelerated renal damage. However, the clinical impact of serum uric acid level on patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) is unknown. We aimed to evaluate the impact of hyperuricemia on such patients. A retrospective study was performed to obtain patients' demographic, clinical, and laboratory data from when they were diagnosed with MPA and GPA. Multivariable logistic regression and Cox hazard model analyses were performed to evaluate factors associated with hyperuricemia at diagnosis and predictive factors of end-stage renal disease (ESRD) development. Among 156 patients, 35 (22.4%) had hyperuricemia at baseline. Hyperuricemic patients had renal manifestation and impaired renal function more frequently than non-hyperuricemic patients. Logistic regression analysis revealed that serum creatinine was significantly associated with hyperuricemia at diagnosis [odds ratio 1.995; 95% confidence interval (CI), 1.503-2.648; P < 0.001]. Cox hazard model analysis revealed that body mass index and serum creatinine were significantly associated with ESRD when all variables were included, but hyperuricemia was independently associated with ESRD [hazard ratio (HR), 3.799; 95% CI 1.719-8.222; P < 0.001) when serum creatinine was excluded. Additionally, in a subgroup analysis of patients with decreased glomerular filtration rates (GFRs), serum uric acid was the sole predictor of ESRD (HR, 1.243; 95% CI 1.048-1.475; P = 0.013). Hyperuricemia is associated with renal damage and ESRD occurrence in MPA and GPA patients. Serum uric acid level is associated with ESRD occurrence in patients with decreased GFRs.