XDH and chronic kidney disease: In contrast, in the Controlled Trial of Slowing of Kidney Disease Progression from the Inhibition of Xanthine Oxidase, which was a randomized-controlled trial with 363 CKD patients in Australia and New Zealand, allopurinol did not slow the decrease in eGFR in patients with CKD stage 3 or 4 at the 104-week follow-up, although the average SUA level decreased to under 6.0 mg/dL in the allopurinol group [25].