Background/Purpose: Although gout is accompanied by the substantial burden of kidney disease, there is limited data to assess renal function as a therapeutic target. There remains some discordance between the indication and goal of urate-lowering therapy (ULT) and unanswered questions about its effects on renal function. Thus, we evaluated the clinical importance of implementing the “treat-to-target” approach in the long-term management of gout in relation to renal function and the factors influencing this outcome.

Methods: In this 10-year retrospective study, the research subjects consisted of patients with gout who were newly treated with allopurinol (n = 42), febuxostat (n = 145), or benzbromarone (n = 57) and had continued ULT for at least 1 year. The upward titration of ULT doses was recommended according to the “treat-to-target” approach proposed by major international rheumatology groups such as the American College of Rheumatology and the European League Against Rheumatism. The efficacy of ULT in improving renal function was investigated through a sequential comparison of the estimated glomerular filtration rate (eGFR) after the duration of ULT. Multivariate logistic regression was used to assess the factors associated with the improvement in renal function.

Results: Out of 719 patients, a total of 244 subjects with a diagnosis of gout who received ULT for more than 12 months were enrolled in this study. The study population was predominantly male (96.7%). The mean age was 50.9 ± 14.2 years, and 17.6% were ≥65 years old. A serum uric acid (SUA) target concentration of < 6 mg/dL was attained for 191 patients (78.3%). Improvement in renal function was only demonstrated in the subjects in whom the SUA target was achieved (76.40 ± 18.81 mL/min/1.73 m2 vs. 80.30 ± 20.41 mL/min/1.73 m2, p < 0.001). A statistically significant difference in the mean change in eGFR with respect to SUA target achievement was apparently shown in individuals with chronic kidney disease (CKD) stage 3 (-0.35 ± 3.87 mL/min/1.73 m2 vs. 5.33 ± 11.64 mL/min/1.73 m2, p = 0.019). The patients who developed acute kidney injury during ULT had a considerable decline in the mean eGFR as opposed to the rest of the patients (-13.21 ± 16.26 mL/min/1.73 m2 vs. 4.23 ± 12.73 mL/min/1.73 m2, p < 0.001). There was no significant difference in the proportion of subjects with improved renal function (p = 0.543) and the mean change in eGFR (p = 0.101) among the three groups of urate-lowering agents selected for ULT. Multivariate analysis predicted that patients ≥65 years old had a decreased likelihood of improvement in renal function (OR 0.35, 95% CI 0.15-0.85, p = 0.020).

Conclusion: This study clarifies that long-term SUA lowering to below 6 mg/dL after initiation of ULT is associated with the significant improvement of renal function in patients with gout, which has proven to be highly beneficial for conditions associated with renal impairment. The proper utilization of the “treat-to-target” approach in clinical practice would provide implications for better management and outcomes not only in gouty arthritis but also in comorbid kidney disease.

« Back to 2019 ACR/ARP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-role-of-a-treat-to-target-approach-on-long-term-renal-outcomes-in-patients-with-gout/