A simplified and validated ultrasound scoring system to evaluate synovitis of bilateral wrists and hands in patients with rheumatoid arthritis

Abstract

The objective of this study was to develop and validate an optimal simplified combination of joints for ultrasonographic assessment of synovitis in wrists and hands in patients with rheumatoid arthritis (RA). Twenty-two joints, including bilateral wrists, all proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joints, were evaluated by grey-scale (GS) and power Doppler (PD) ultrasound using semi-quantitative scoring systems in 705 RA patients. Candidate joint sets were then selected by multiple linear regression analysis and the optimal candidate set was eventually validated in 235 RA patients. Through multiple linear regression analysis, the standard coefficient (β) of MCP2, MCP3, and MCP5 joints in terms of GS was higher than other joints. The adjusted R ² of the model composed of wrist, MCP2, MCP3, and MCP5 joints was greater than 0.9. Among the sum GS and PD scores of various selected joint combinations, total score-8, including bilateral wrist, MCP2, MCP3, and MCP5 joints, not only showed highest sensitivity and negative predictive value (93.86 and 92.90% for GS; 97.20 and 97.21% for PD, respectively) but also the best correlation with the total score-22 (r = 0.955 and 0.972 for GS and PD). The score-8 was further validated in 235 RA patients. The sensitivity for detecting synovitis by GS and PD was 94.35 and 94.12%, and the negative predictive values were 94.07 and 95.68%, respectively. Total score-8 system, including bilateral wrist, MCP2, MCP3, and MCP5 joints, is simple and efficient to pick up active synovitis of wrists and hands in patients with RA in daily practice.

Keywords: Rheumatoid arthritis; Scoring system; Synovitis; Ultrasonography; Wrists and hands.