Urate-Lowering Therapy in Moderate to Severe Chronic Kidney Disease.

CONTEXT

Hyperuricemia is an independent risk factor for progression of kidney disease.

OBJECTIVE

To determine whether lowering serum uric acid level (sUA) to below 6 mg/dL (target) improves mild to moderate chronic kidney disease (CKD) and whether CKD stage influences the benefit of lowering sUA to target.

DESIGN

Retrospective epidemiologic cohort study conducted over 8 years. Estimated glomerular filtration rate (eGFR) was required in the 6 months preceding the index date (defined as first occurrence of sUA < 7 mg/dL), and at least 1 sUA and eGFR were required during follow-up. Patients were urate-lowering therapy (ULT) naïve, aged 18 years or older, and had CKD Stages 2 to 4 at baseline. Health Plan enrollment with drug benefit was required. Exclusions included active cancer, dialysis, or other kidney disease.

MAIN OUTCOME MEASURES

A 30% decrease or 30% improvement in eGFR from baseline.

RESULTS

A total of 12,751 patients met inclusion criteria; 2690 patients received ULT during follow-up and 10,061 did not. Target sUA was achieved in 1118 patients (42%) receiving ULT. A 30% improvement in eGFR was likelier in patients who achieved the target (odds ratio [OR] = 1.78, p < 0.001). Pairwise comparison of CKD stages showed a 30% improvement in eGFR in CKD Stage 2 (OR = 2.26, p = 0.017) and Stage 3 (OR = 2.23, p < 0.001) but not Stage 4 (OR = 1.50, p = 0.081).

CONCLUSION

Patients who achieve an American College of Rheumatology target sUA below 6 mg/dL during ULT have higher rates of eGFR improvement, especially in CKD Stages 2 and 3.