Objective. To evaluate the metrologic properties of composite disease activity indices in rheumatoid arthritis (RA), utilizing information derived from clinical, gray-scale (GS), and power Doppler (PD) ultrasound examinations, and to assess the classification of patients according to disease activity using such indices. Methods. This ancillary study utilized data from a multicenter, prospective, randomized, parallel-group study conducted in subjects with moderate RA randomized to receive etanercept and methotrexate (ETN ؉ MTX) or usual care (various disease-modifying antirheumatic drugs [DMARDs]). In multimodal indices, the 28 swollen joint count was either supplemented or replaced by clinically nonswollen joints in which the presence of synovitis was detected either by GS and/or PD and was calculated according to the Disease Activity Score in 28 joints (DAS28) or the Simplified Disease Activity Index (SDAI). Reliability, external validity, and discriminative capacity were calculated at baseline/screening by intraclass correlation coefficient, Pearson's correlation, and standardized response mean, respectively.
Results. Data from 62 patients (mean