Long-Term Follow-up of a Randomized Controlled Trial of Allopurinol Dose Escalation to Achieve Target Serum Urate in People With Gout.

Objective: To determine the long-term use of and adherence to urate-lowering therapy (ULT), serum urate (SU) control, and self-reported flares in participants from a randomized controlled trial of allopurinol dose escalation, in order to achieve target SU concentration (< 0.36 mmol/L) in people with gout.

Methods: For surviving study participants, ULT dispensing and SU testing within the preceding 12 months was obtained by medical record review. A phone interview was conducted to determine self-reported flares and adherence.

Results: Over a mean follow-up of 6.5 (SD 2.5) years since enrollment, 60 out of 183 (33%) participants had died. Review of the 119 surviving participants showed that 98 (82%) were receiving allopurinol, 5 (4%) were receiving febuxostat, and 10 (8%) were not receiving ULT; for the remaining 6 (5.0%), ULT use could not be determined. In those receiving allopurinol, the mean dose was 28.1 (range -600 to 500) mg/day lower than at the last study visit; 49% were receiving the same dose, 18% were on a higher dose, and 33% were on a lower dose than at the last study visit. SU values were available for 86 of the 119 (72%) participants; 50 out of 86 (58%) participants had an SU concentration of < 0.36 mmol/L. Of the 89 participants who participated in the phone interview, 19 (21%) reported a gout flare in the preceding 12 months and 79 (89%) were receiving allopurinol; 71 (90%) of those receiving allopurinol reported 90% or greater adherence.

Conclusion: Most of the surviving participants in the allopurinol dose escalation study had good real-world persistence with allopurinol, remained at target SU, and had a low number of self-reported flares.