Post-Hoc Analysis of Two Gout Remission Definitions in a Two-Year Randomized Controlled Trial of Nurse-Led Versus Usual Gout Care

Abstract

Objective: To compare the performance of the 2016 preliminary gout remission definition and a simplified gout remission definition in a clinical trial of nurse-led gout care.

Methods: Data from a 2-year parallel arm, non-blinded, randomised controlled trial of 517 community-derived people with gout were analyzed. Participants were assigned 1:1 to receive nurse-led care or general practitioner usual care. Remission was defined using the 2016 preliminary gout remission definition and a simplified gout remission definition without patient reported outcomes. Binary logistic regression was used to compare intervention groups. General linear models were used to compare Gout Impact Scale (GIS) scores between those in remission and those not in remission using either definition.

Results: Participants in the nurse-led care group were more likely to achieve remission using either definition; at Year 2 the odds ratio was 7.92 [95 % CI 4.86–12.92] using the 2016 preliminary definition and 11.88 [95 % CI 7.49–18.84] using the simplified definition. For all participants, the 2016 preliminary definition was fulfilled by 9.9 % at Year 1 and 28.4 % at Year 2, p < 0.001 and the simplified definition was fulfilled by 17.6 % at Year 1 and 42.7 % at Year 2, p < 0.001. People in remission using either definition had better gout outcomes assessed using the GIS, including greater control over their gout.

Conclusion: Both definitions discriminated between the intervention groups and showed high construct validity. The simplified definition identified more people as being in gout remission at Year 1 and Year 2. The simplified definition is a feasible and valid option for defining gout remission.