TitleEffects of allopurinol dose escalation on bone erosion and urate volume in gout: a dual energy CT imaging study of a randomized controlled trial
OBJECTIVE To examine whether dose escalation of allopurinol to achieve serum urate target can influence bone erosion or monosodium urate (MSU) crystal deposition as measured by DECT in people with gout.
METHODS We conducted an imaging study of a two-year randomized clinical trial of immediate allopurinol dose escalation to serum urate (SU) target vs. conventional dosing for one year followed by dose escalation to target (control) in people with gout on allopurinol with SU ≥0.36mmol/L. DECT scans of the feet, and radiographs (XR, hand and foot) were obtained at the baseline, Year 1 and Year 2 visits. DECT scans were scored for bone erosion and urate volume.
RESULTS Paired imaging data were available for 87 participants (45 control, 42 dose escalation). At Year 2, the progression in CT erosion score was higher in the control group compared with the dose escalation group (+7.8% for the control group and +1.4% for the dose escalation group, P randomization =0.015). Changes in XR erosion or narrowing scores did not differ between groups. Reductions in DECT urate volumes were observed in both randomization groups. At Year 2, participants in the control group with SU<0.36mmol/L and the dose escalation group had reduced DECT urate volume (-27.6 to -28.3%), whereas reduction in urate volume was not observed in the control group with SU ≥0.36mmol/L (+1.5%, P urate*randomization =0.023).
CONCLUSION These findings provide evidence that long-term urate-lowering therapy using a treat to serum urate target strategy can influence structural damage and reduce urate crystal deposition in gout. This article is protected by copyright. All rights reserved.