Verification of an ultrasonographic scoring system in discriminating rheumatoid arthritis from osteoarthritic and normal joints in an Egyptian cohorts

Abstract

Background The use of musculoskeletal ultrasound in rheumatoid arthritis (RA) has been growing over the last decades mainly to monitor response to treatment and for early detection of erosions. Suggestions to include this technique in the diagnosis of RA have been made, but not yet been implemented (because of the lack of specific sonographic criteria for RA). Objectives To verify the performance of a proposed combined structural and synovial scoring system in differentiating RA from osteoarthritis (OA) and healthy sonographic findings in the small joints of the hand. Patients and methods Twenty RA patients, 20 patients with hand OA, and 10 healthy controls were subjected to musculoskeletal ultrasound of the metacarpophalyngeal and proximal interphalyngeal joints. The novel proposed scoring system was applied characterizing each joint as either RA supported or RA unsupported. Grading of synovitis as mild, moderate, or severe was also performed. In the RA group, disease activity was assessed by Disease Activity Score 28 (DAS28) and anticyclic citrullinated peptide serum levels were measured. Results When one or more RA-supported joints were detected using this scoring system, it had a sensitivity of 100.0% and a specificity of 83.0%, with a diagnostic accuracy of 90.0%, for the diagnosis of RA. If two or more joints were detected, it had a sensitivity of 95.0% and a specificity of 96.7%, with a diagnostic accuracy of 96.0% for the diagnosis of RA. Conclusion The novel suggested combined structural and synovial scoring system showed high performance in differentiating RA from OA and controls.

Keywords

• musculoskeletal ultrasound, osteoarthritis, rheumatoid arthritis