Tenosynovitis US scoring systems follow synovitis and clinical scoring systems in RA and are responsive to change after biologic therapy

To investigate by ultrasonography (US) in a cohort of active RA patients starting biologic therapy the responsiveness of tenosynovitis of wrist and hands compared to the responsiveness of synovitis in a 6 month period follow-up, to compare the responsiveness of finger flexor tenosynovitis with the responsiveness of wrist extensor tenosynovitis and to describe the subclinical synovitis and tenosynovitis in RA patients in clinical remission. Fifty seven patients with active RA starting biologic therapy were included. Clinical, laboratory, and US evaluations were performed at baseline, 1, and 6 months. US evaluation included wrist and MCPs 2-5 joints, bilaterally for synovitis and extensor tendons compartments 2, 4, and 6 and finger flexors 2-5 for tenosynovitis. Eighteen US scores based on semiquantitative or binary grades were calculated at each visit. Responsiveness of synovitis and tenosynovitis scores was calculated using the standardized response mean (SRM). The responsiveness of US tenosynovitis was lower comparing with the responsiveness of US synovitis but both showed large effect of therapy. Furthermore, tenosynovitis responsiveness was similar to CRP responsiveness (SRM -0.90). Finger flexors tenosynovitis showed a higher responsiveness than extensor tenosynovitis on GS (-0.94 compared to -0.63) and a lower SRM on PD (-0.56 compared to -0.85). Tenosynovitis scores remission was overlapping clinical remission according to CDAI and SDAI in 100% of cases. Overall there was less subclinical tenosynovitis than subclinical synovitis at final visit according to clinical activity indices. Tenosynovitis US scoring in RA may be as good as synovitis scoring for characterization of disease activity and responsiveness.