Multibiomarker disease activity score and C-reactive protein in a cross-sectional observational study of patients with rheumatoid arthritis with and without concomitant fibromyalgia

Rheumatology (Oxford). 2016 Apr;55(4):640-8. doi: 10.1093/rheumatology/kev388. Epub 2015 Nov 25.


Objectives: To examine the association between a multibiomarker disease activity (MBDA) score, CRP and clinical disease activity measures among RA patients with and without concomitant FM.

Methods: In an observational cohort of patients with established RA, we performed a cross-sectional analysis comparing MBDA scores with CRP by rank correlation and cross-classification. MBDA scores, CRP and clinical measures of disease activity were compared between patients with RA alone and RA with concomitant FM (RA and FM) by univariate and multivariate analyses.

Results: CRP was ⩽1.0 mg/dl for 184 of 198 patients (93%). MBDA scores correlated with CRP (r = 0.755, P < 0.001), but were often discordant, being moderate or high for 19%, 55% and 87% of patients with CRP ⩽0.1, 0.1 to ⩽0.3, or 0.3 to ⩽1.0 mg/dl, respectively. Among patients with CRP ⩽1.0 mg/dl, swollen joint count (SJC) increased linearly across levels of MBDA score, both with (P = 0.021) and without (P = 0.004) adjustment for CRP, whereas CRP was not associated with SJC. The 28-joint-DAS-CRP, other composite measures, and their non-joint-count component measures were significantly greater for patients with RA and FM (n = 25) versus RA alone (n = 173) (all P ⩽ 0.005). MBDA scores and CRP were similar between groups.

Conclusion: MBDA scores frequently indicated RA disease activity when CRP did not. Neither one was significantly greater among patients with RA and FM versus RA alone. Thus, MBDA score may be a useful objective measure for identifying RA patients with active inflammation when CRP is low (⩽1.0 mg/dl), including RA patients with concomitant FM.

Keywords: C-reactive protein; RAPID3; biomarkers; disease activity; fibromyalgia; multibiomarker; rheumatoid arthritis.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antirheumatic Agents / therapeutic use
  • Arthritis, Rheumatoid / complications
  • Arthritis, Rheumatoid / diagnosis*
  • Arthritis, Rheumatoid / drug therapy
  • Biomarkers / blood
  • C-Reactive Protein / metabolism*
  • Cross-Sectional Studies
  • Female
  • Fibromyalgia / etiology*
  • Humans
  • Male
  • Middle Aged
  • Severity of Illness Index


  • Antirheumatic Agents
  • Biomarkers
  • C-Reactive Protein