Do People With Tophaceous Gout Require More Allopurinol for Good Clinical Outcomes? Analysis of 2 Randomized Controlled Trials of Allopurinol Dose Escalation

Objective Current prescribing recommendations support higher doses of allopurinol in tophaceous gout to accomplish full control of gout and to lower serum uric acid to normal or near-normal levels. The aim of this study was to determine whether outcomes differ between individuals with and without tophi during 1 year of allopurinol prescribed according to a serum urate (SU) target. Methods Individual-level participant data from 2 randomized trials of gout (n = 383) were analyzed. Both trials used a treat-to-target strategy with allopurinol and an SU target of < 0.36 mmol/L. The primary outcome was the percentage of participants at target-level SU at month 12 among those with and without tophi. Secondary outcomes included the absence of gout flares. The percentages of participants with target- level SU and the absence of gout flares were compared between those with and without baseline tophi using the Cochran-Mantel-Haenszel test, controlling for study. Results Most participants were male, were of European ethnicity, and had longstanding gout. Tophi were present in 33% of participants. There was no statistically significant difference in the percentage of participants with target-level SU at 12 months between those with and without tophi (70.3% vs 73.6%; P = 0.76) nor in the percentage of participants without gout flares during the month before month 12 between those with and without tophi (71.4% vs 79.7%; P = 0.27). Conclusion Despite the higher monosodium urate crystal burden in those with tophi, key gout outcomes, including urate-lowering efficacy and absence of gout flares, did not differ from those without tophi when allopurinol was prescribed.