Measures of Disease Activity in Rheumatoid Arthritis: A Clinician's Guide

Developments in the treatment of rheumatoid arthritis (RA) have highlighted the need for objective disease activity indices applicable to both research and clinical settings and this area has become an important area of research. Previously, the American College of Rheumatology (ACR) response criteria were the most commonly used measures of response in clinical trials, but because they were not developed to measure individual responses to therapy in a clinical setting, the recent focus has been on the, development of indices that provide continuous, rather than relative, measures of improvement. Although the Disease Activity Score (DAS) and DAS28 have been the most commonly used of these continuous measures, these indices are perceived by some to be difficult to perform in busy outpatient settings. Therefore, indices based on simpler equations and/or fewer elements, and indices based entirely on patient-reported data have been proposed as alternatives. This review discusses each of these major disease indices and focuses on the most recent developments in their validation and application to clinical care.