The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) definition of clinical remission in gout

Abstract

Objectives: In 2016, rheumatologists and gout researchers developed a preliminary definition for gout remission. A subsequent qualitative study involving people with gout identified redundancies in the preliminary definition, prompting the development of a simplified definition consisting of no gout flares over 12 months, absence of subcutaneous tophi and serum urate <0.36 mmol/L (6 mg/dL) over 12 months. Here, we describe the evaluation and validation of the simplified definition and endorsement of this definition as the Gout, Hyperuricemia, and Crystal-Associated Disease Network (G-CAN) definition of clinical remission in gout. Methods: After establishment of the simplified definition, this multiphase project involved consecutive steps: analysis of the definition across a range of gout clinical trial datasets and study populations, summary of evaluation and validation of this definition presented to G-CAN members, discussion of this definition by G-CAN members, voting and G-CAN Board endorsement. Results: The simplified definition exhibited face validity, construct validity, predictive validity, feasibility, responsiveness, and discrimination across a range of gout clinical trial datasets. It also captured both inflammatory disease activity and urate burden in gout and reflected the patient perspective on gout remission. It was suggested by G-CAN members to consider the definition as one for ‘clinical gout remission’ since there is no domain evaluating complete crystal dissolution. In voting, this definition was supported by 98% of G-CAN members, and the G-CAN Board endorsed the definition. Conclusions: The G-CAN definition is feasible and has high validity. We recommend that this definition is used when assessing clinical remission in gout.