Allopurinol and Chronic Kidney Disease

To the Editor: The uric acid hypothesis proposes that hyperuricemia or gout increases the risk of progression of chronic kidney disease and is based on studies showing exponentially increased risk when serum urate levels exceed 7 mg per deciliter.^1-3 Both the PERL (Preventing Early Renal Loss in Diabetes) trial conducted by Doria et al. and CKD-FIX (Controlled Trial of Slowing of Kidney Disease Progression from the Inhibition of Xanthine Oxidase) conducted by Badve et al. (June 25 issue)^4,5 included normouricemic participants and did not directly test this hypothesis. The PERL trial, which did not show a benefit with allopurinol, was . . .