Target Serum Urate Achievement and Chronic Kidney Disease Progression in Patients With Gout and Kidney Disease.

Importance: Clinicians often approach urate-lowering therapy (ULT) cautiously in patients with gout and impaired kidney function because they are concerned about the risk of progression to severe or end-stage kidney disease. However, evidence from randomized clinical trials of this association remains inconclusive.

Objective: To evaluate the association between achieving target serum urate level with ULT and progression of chronic kidney disease (CKD) to severe or end-stage in patients with gout and impaired kidney function.

Design, setting, and participants: This was a cohort study using the target trial emulation approach using data from a general practice database (IQVIA Medical Research Database) for 2000 to 2023. Eligible patients were 40 to 89 years old and had gout and CKD stage 3. Data analyses were performed from November 2023 to September 2024.

Exposures: Lowering serum urate level to target level (<6 mg/dL) using ULT.

Main outcomes and measures: Severe or end-stage kidney disease, determined by an estimated glomerular filtration rate of less than 30 mL/min/1.73 m2 on at least 2 occasions more than 90 days apart within 1 year, or at least 1 Read code (per the Refined Etiology, Anatomical Site, and Diagnosis classification) for CKD stages 4 or 5, hemodialysis, peritoneal dialysis, or kidney transplant. The prespecified noninferiority margin of the hazard ratio (HR) was set at 1.2, comparing those who achieved the target serum urate level with those who did not.

Results: Among the 14 792 participants (mean [SD] age, 73.1 [9.5] years; 9215 men [62.3%] and 5577 women [37.7%]) with gout and with CKD stage 3, the 5-year risk of severe or end-stage kidney disease was 10.32% for those who achieved the target serum urate level and 12.73% for those who did not. Compared with those not achieving the target level, the adjusted 5-year risk difference and HR of severe or end-stage kidney disease for patients achieving the target serum urate level was -2.41% (95% CI, -4.61% to -0.21%) and 0.89 (95% CI, 0.80 to 0.98), respectively.

Conclusions and relevance: The findings of this cohort study indicate that in patients with gout and CKD stage 3, lowering serum urate level to less than 6 mg/dL vs 6 mg/dL or greater using ULT was not associated with an increased risk of severe or end-stage kidney disease. These findings support optimizing ULT to achieve target serum urate levels when treating patients with gout and impaired kidney function.