Concurrent validity of provisional remission criteria for gout: a dual-energy CT study

• Main Authors: Nicola Dalbeth, Christopher Frampton, Maple Fung, Scott Baumgartner, Savvas Nicolaou, Hyon K. Choi
• Format: Article
• Language: English
• Published: BMC 2019-06-01
• Series: Arthritis Research & Therapy
• Subjects: Gout; Urate; Outcome measures; Remission; Dual-energy CT
• Online Access: http://link.springer.com/article/10.1186/s13075-019-1941-8

Abstract Background Provisional gout remission criteria including five domains (serum urate, tophus, flares, pain due to gout, and patient global assessment) have been proposed. The aim of this study was to test the concurrent validity of the provisional gout remission criteria by comparing the criteria with dual-energy CT (DECT) findings. Methods Patients with gout on allopurinol ≥ 300 mg daily were prospectively recruited into a multicenter DECT study. Participants attended a standardized study visit which recorded gout flare frequency in the preceding 12 months, physical examination for tophus, serum urate, and patient questionnaires. DECT scans of both hands/wrists, feet/ankles/Achilles, and knees were analyzed by two DECT radiologists. The relationship between the DECT urate crystal volume and deposition with individual domains as well as the provisional remission criteria set was analyzed. Results The provisional remission criteria were fulfilled in 23 (15.1%) participants. DECT urate crystal deposition was observed less frequently in those fulfilling the provisional remission criteria (44%), compared with those not fulfilling the criteria (73.6%, odds ratio 0.28, P = 0.004). The median (range) DECT urate crystal volume was 0.00 (0.00–0.46) cm3 for those fulfilling the remission criteria, compared with 0.08 (0.00–19.53) cm3 for those not fulfilling the criteria (P = 0.002). In multivariate regression analysis, the serum urate and tophus domains were most strongly associated with DECT urate crystal deposition. Conclusions In people with gout established on allopurinol, a state of remission as defined by the provisional remission criteria is associated with less DECT urate crystal deposition. While this study provides support for the validity of the provisional gout remission criteria, it also demonstrates that some crystal deposition may be present in people achieving these criteria.