The 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for rheumatoid arthritis (RA) refer to a possible use of ultrasound "for confirmation of the clinical findings." We undertook this study to determine the optimized definition of ultrasound-detected synovitis for the 2010 ACR/EULAR criteria and to assess the impact of its use on the accuracy of RA classification.
One hundred nine patients with musculoskeletal symptoms for ≤3 years were enrolled in the study. Patients underwent clinical, laboratory, radiographic, and comprehensive ultrasonographic assessments at baseline and received routine management from expert rheumatologists who were blinded to the ultrasound findings.
Sensitivity and specificity of the 2010 ACR/EULAR criteria using different definitions of synovitis to identify patients who developed a disease requiring methotrexate (MTX) treatment within 1 year were 58.5% and 79.4%, respectively, for clinical synovitis (tenderness or swelling), 78.0% and 79.4%, respectively, for ultrasound-detected synovitis with a gray-scale (GS) imaging score≥1 (GS≥1 ultrasound synovitis), and 56.1% and 93.7%, respectively, for GS≥2 ultrasound synovitis or a synovial power Doppler (PD) signal score≥1 (GS≥2/PD≥1 ultrasound synovitis). Receiver operating characteristic curve analysis for the criteria scores revealed the largest area under the curve with GS≥2/PD≥1 ultrasound synovitis.
Ultrasound assessment improves the accuracy of the 2010 ACR/EULAR criteria for identifying patients with a disease requiring MTX treatment. Our data provide preliminary but vital information for the methodology to confirm the presence of synovitis using ultrasound in the 2010 ACR/EULAR criteria.