Objectives: To evaluate different global ultrasonographic (US) synovitis scoring systems as potential outcome measures of Rheumatoid Arthritis (RA) according to the OMERACT filter.
Patients-Methods: 1. Selected global scoring systems: for both the clinical, B-mode and Power Doppler techniques, the following joints were evaluated: 28 joints (DAS28), 20 joints (MCPs+MTPs) and 38 joints (28+MTPs) using either a binary (yes/no) or a 0-3 grade. 2. Study design: Prospective, 4 months follow-up of 76 RA patients requiring anti-TNF therapy (complete follow-up data: 66 patients) 3. Analysis: 3.a. intra-observer reliability was evaluated using the intra-class coefficient of correlation (ICC), 3.b. validity, 3.b.1. construct validity using the Cronbach’s alpha test and 3.b.2. external validity using level of correlation between scoring system and CRP; 3.c. sensitivity to change was evaluated using the Standardized Response Mean; 3.d. discriminating capacity was evaluated using the Standardized Mean Differences in patients considered by the physician as significantly improved or not at the end of the study.
Results: Different clinimetric properties of various US scoring systems were at least as good as the clinical scores with as examples intra-observer reliability ranging from 0.61 to 0.97 versus from 0.53 to 0.82, construct validity ranging from 0.76 to 0.89 versus from 0.76 to 0.88, correlation with CRP ranging from 0.28 to 0.34 versus from 0.28 to 0.35, sensitivity to change ranging from 0.60 to 1.21 versus from 0.96 to 1.36 for US versus clinical scoring systems respectively.
Conclusion: This study suggests that US evaluation of synovitis is an outcome measure at least as relevant as physical examination. Other studies are required in order to achieve optimal US scoring systems for monitoring RA patients both in clinical trials and in clinical practice.