WASHINGTON – Urate lowering therapy improved kidney function in patients with chronic kidney disease (CKD), according to a large retrospective study presented at the annual meeting of the American College of Rheumatology. Moreover, patients with CKD stage 3 derived the most benefit from urate lowering therapy, and those with CKD stage 2 also benefited to a lesser degree. Patients with CKD stage 4 had no benefit from urate lowering therapy.
“Two years ago we showed that urate lowering therapy did not worsen kidney function in patients with chronic kidney disease. This study shows that their kidney function improved [with urate lowering therapy],” said Gerald D. Levy, MD, MBA, a rheumatologist at Kaiser Permanente of Southern California, Downey, Calif.
The study was conducted from 2008 to 2014 and included 12,751 patients with serum urate levels of above 7 mg/dL and CKD Stages 2, 3, and 4 at the index date, defined as the first time this test result was reported. Patients were drawn from the Kaiser Permanente database and were treated by primary care physicians. Patients were followed for 1 year from the index date. The primary outcome measure was a 30% increase or a 30% decrease in glomerular filtration rate (GFR) from baseline to the last available result.
Of the 12,751 patients, 2,690 were on urate lowering therapy and 10,061 were not on urate lowering therapy. Goal serum urate (sUA) was achieved in 1,118 (42%) of patients on urate lowering therapy. Among patients who achieved goal sUA, a 30% improvement in GFR was observed in 17.1% versus 10.4% of patients who did not achieve sUA goal, for an absolute difference of 6.7% (P less than .001).
For patients at goal versus those not at goal, the ratio of improvement was 3.4 and 3.8, respectively.
“This study suggests that patients with CKD should be tested for uric acid independent of whether they have gout or not. Getting to goal is important. Stage 3 CKD is the sweet spot where patients got the most pronounced benefit from urate lowering therapy,” he stated. “Stage 4 CKD is too late.”
Dr. Levy discussed the findings in a video interview during the meeting.