Is ultrasound a better target than clinical disease activity scores in rheumatoid arthritis with fibromyalgia? A case-control study

PLoS One. 2015 Mar 4;10(3):e0118620. doi: 10.1371/journal.pone.0118620. eCollection 2015.


Objectives: Our goal is to study the correlations among gray-scale seven-joint ultrasound score (GS-US7), power Doppler seven-joint ultrasound score (PD-US7), disease activity score-28 joints (DAS28), simplified disease activity index (SDAI) and clinical disease activity index (CDAI) in patients with and without fibromyalgia (FM).

Methods: A matched case-control study included all patients consecutively seen in the Rheumatoid Arthritis (RA) Clinic. Participants were allocated into one of two groups: RA with FM and RA without FM. Ultrasound (US) and clinical scoring were blinded for the presence of FM. Medians and proportions were compared by Mann-Whitney's test and McNemar's test, respectively. Spearman's rank correlation coefficients (rs) were calculated among clinical and US scores and differences were tested by r-to-z transformation test.

Results: Seventy-two women were included, out of 247 RA patients, mostly white, with median (IQR) age of 57.5 (49.3-66.8) years, with RA symptoms for 13.0 (6.0-19.0) years and FM symptoms for 6.0 (2.0-15.0) years. Disease-modifying antirheumatic drugs, non-steroidal anti-inflammatory drugs and prednisone use was comparable between groups. Objective activity parameters were not different between groups. RA patients with FM had greater DAS28, SDAI and CDAI but similar GS-US7 and PD-US7. GS-US7 correlated with DAS28, SDAI and CDAI in patients with and without FM (rs = 0.36-0.57), while PD-US7 correlated with clinical scores only in patients without FM (rs = 0.35-0.38).

Conclusion: To our knowledge, this is the first study to demonstrate that ultrasound synovitis scores are not affected by FM in RA patients. PD-US7 performed better than GS-US7 in long-standing RA patients with DAS28, SDAI or CDAI allegedly overestimated due to FM. Since sonographic synovitis predicts erosion better than swollen joint count, C-reactive protein and erythrocyte sedimentation rate, US should be considered a promising treatment target in RA patients with FM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Arthritis, Rheumatoid / complications*
  • Arthritis, Rheumatoid / diagnostic imaging*
  • Arthritis, Rheumatoid / therapy
  • Case-Control Studies
  • Female
  • Fibromyalgia / complications*
  • Humans
  • Joints / diagnostic imaging
  • Joints / pathology
  • Joints / physiopathology
  • Middle Aged
  • Ultrasonography

Grants and funding

This study was funded by Fundo de Incentivo à Pesquisa e Eventos of Hospital de Clínicas de Porto Alegre. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.