Background Dual energy computed tomography (DECT) allows reliably detecting and quantifying tophus burden in patients with chronic gout. Longitudinal studies on the effect of uric acid lowering drug therapy on tophus burden assessed by DECT are currently lacking with the exception of a small study performed in patients treated with pegloticase (1)
Objectives To assess the effects of uric acid lowering drug therapy to reduce tophus volume in patients with chronic gout
Methods Follow-up DECT scans were performed in 94 patients with DECT+ chronic gout receiving stable treatment with either allopurinol, febuxostat, benzbromaron or pegloticase, or had life-style intervention only with no concomitant uric acid lowering drug therapy. Baseline and follow-up scans of both feet captured tophus volume by Syngo DE Gout software (Siemens). Artefacts were manually excluded. Changes in tophus volume were calculated in a descriptive (tophus volume at baseline minus tophus volume at follow-up) and inferential way (Wilcoxon signed-rank test). Demographic data, medication and blood values (CRP, creatinine, serum urate) were recorded at the time of DECT scan.
Results 94 patients (75 men and 19 women) were analyzed. Mean disease duration until the first DECT examination was 3.3 years and mean interval between both DECT examinations was 1.5 years. The overall baseline serum uric acid level decreased from 7.3 ± 2.5 mg/dl to 5.9 ± 2.8 mg/dl at follow up. Baseline tophus volume decreased by 77% with allopurinol (p<0.001, r=-0.50), 35% with febuxostat (p=0.001, r=-0.51) and 90% with pegloticase (p=0.005, r=-0.58). Only 2 patients were treated with benzbromaron showing numerical decrease of tophus volume at a similar range as seen with allopurinol (-75%). Life-style intervention also led to a moderate (-31%), though significant (p=0.007, r=-0.40), decrease in tophus burden.
Conclusions Sustained uric acid lowering drug therapy leads to significant reduction of DECT tophus burden in chronic gout patients. Tophus reduction depends on initial tophus volume.
) Tophus resolution with pegloticase: a prospective dual-energy CT study. Araujo EG, Bayat S, Petsch C, Englbrecht M, Faustini F, Kleyer A, Hueber AJ, Cavallaro A, Lell M, Dalbeth N, Manger B, Schett G, Rech J. RMD Open. 2015 Jun 17;1(1):e000075. doi: 10.1136/rmdopen-2015-000075. eCollection 2015.
Disclosure of Interest None declared
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