Background Hyperuricemia was a risk factor for hypertension, metabolic syndrome, type 2 diabetes mellitus, cardiovascular disease, and chronic kidney disease. Uric acid lowering therapy was indicated when hyperuricemic patients with established diagnosis of gout. Clinical trials have demonstrated that xanthine oxidase inhibitor decreased the progression of chronic kidney disease in gout patients. Uric acid lowering therapy was not suggested in asymptomatic hyperuricemic patients due to lack of evidence.
Objectives To evaluate the association between the change of uric acid level and renal function in chronic kidney disease patients with/without gout.
Methods This is a retrospective cohort study. The data source was the electronic records of National Taiwan University Hospital and its branch Hospital during 2011 to 2015. Patients were included if they have chronic kidney disease stage 2, 3, and 4 according to K-DOQI staging and receive follow-up for more than 6 months. Multiple variables linear regression models were applied for evaluating the association between the change of uric acid level and eGFR. The variables including age, gender, hypertension, type 2 diabetes mellitus, dyslipidemia, gout, and initial uric acid level were analyzed. We performed a subgroup analysis of the patients with decreasing uric acid level.
Results Total 272 patients were included. There were 154 (56.6%) females and 118 (43.4%) males. The mean age was 57.9±14.7 (SD) years. The mean uric acid level was 6.5±1.9 (SD) mg/dL. The mean duration of follow-up was 128.7 ±55.3 (SD) weeks. 52 (19%) patients had the diagnosis of gout. In multivariable linear regression models, the change of eGFR was affected by the change of uric acid level (β= -0.249, P <0.001). In the subgroup analysis of the patients with decreasing uric acid level, the change of eGFR was also affected by the change of uric acid level (β= -0.214, P =0.011).
Conclusions The decreasing uric acid level is associated with increasing eGFR in chronic kidney disease patients even after adjusting the status of gout. The causal relationship between the uric acid level and renal function should be interpreted carefully.
Richette P, Perez-Ruiz F, Doherty M, et al. Improving cardiovascular and renal outcomes in gout: what should we target? Nature Reviews Rheumatology 2014;10(11):654–61.
Disclosure of Interest None declared