Abstract
Background/Aims Preliminary data suggests that elevated serum uric acid levels (sUA) play a significant role in the development of renal disease. Few studies have evaluated urate-lowering therapies (ULT) in a population with hyperuracemia and the impact on development of renal disease. Our aim was to investigate whether initiation and maintenance of ULT, in patients with sUA ≥7.0 mg/dL, has a beneficial impact on renal function as measured by glomerular filter rate (GFR) reductions and adverse renal outcomes.
Methods Patients 18 years and older, with sUA ≥7mg/dL and kidney disease stage 1, 2 or 3 from 01/01/2002 to 12/31/2010 were identified within Kaiser Permanente Southern California. Serum UA levels and GFR were collected at baseline and throughout follow-up for all patients. Patients on ULT were categorized into no-treatment, ≤70% time on treatment, and >70% time on treatment during follow-up. Patients were followed until they had one of the following primary outcomes: new onset dialysis, a 30% reduction in their GFR level from baseline, receipt of a kidney transplant, or a GFR level <15 mL/min/1.72m2. Baseline characteristics between the treatment groups were compared using descriptive statistics. A Cox proportional hazards model was used to estimate the hazard ratio (HR) and 95% confidence intervals (95% CI) associated with ULT treatment controlling for patient characteristics.
Results A total of 33,745 patients were identified (n = 21,481 no-treatment, n = 9,136 ≤70% time on treatment, n = 3,128 >70% time on treatment). Overall, 3,592 patients reached a study endpoint; 2,114 patients in the no-treatment, 1,109 in the ≤70% treatment and 369 in the >70% treatment group. Controlling for demographics and co-morbid conditions, treatment for >70% of the time was associated with a 20% reduction in events (HR = 0.8; 95% CI 0.71–0.90). Factors associated with high risk of events included age, female gender, renal disease, congestive heart failure, and diabetes.
Conclusions Our findings suggest that ULT may preserve renal function, and prevent or delay renal outcomes such as reductions in GFR and time to dialysis.
