Abstract
OBJECTIVE: To assess whether the American College of Rheumatology response criteria ACR20 should be replaced by another definition of response with enhanced discriminant validity. METHODS: We worked with statisticians to define over 100 different ways of defining response, including dichotomous definitions (e.g., ACR20; ACR50; ACR70; low disease activity), ordinal definitions (EULAR response; ACR20, ACR50, ACR70), disease activity indexes [Disease Activity Score (DAS); Disease Activity Index, SDAI], continuous definitions (mean percentage improvement in all core set measures; nACR, ACRn), and hybrid definitions (ACR20, ACR50, ACR70 defined for a patient as 0, 1, 2, 3 scale with continuous measures between intervals) along with variations on each of these approaches (e.g., percentage vs absolute change in DAS; e.g., measures requiring vs not requiring joint count improvement). To test clinical validity, we administered a survey using patients from a trial who had various levels of improvement and asked rheumatologists whether and by how much these patients improved. For Sn-to-Chge, we are collecting data from large disease modifying antirheumatic drug multicenter trials in rheumatoid arthritis and ranking candidate definitions of response on their average p values in distinguishing active treatment from placebo or combination compared to single comparator. RESULTS: We surveyed 52 rheumatologists about which trial patients had improved and by how much. Trial data were obtained and tested for sensitivity to change. CONCLUSION: A rigorous data-driven consensus process was used to reassess the ACR20.
