XDH and hyperuricemia: However, in the current study, the risk of long-term mortality related to hyperuricemia was similar between patients with eGFR ≥60 ml/min/1.73m2 (hyperuricemia mainly caused by reduced UA excretion) and patients with eGFR <60 ml/min/1.73m2 (hyperuricemia mainly caused by increased xanthine oxidase activity).