Rheumatoid arthritis associated to fibromyalgia: factors associated with active synovitis and a proposal of an algorithm for management

Abstract

Introduction: Recent studies have shown that ultrasound (US) assessment of disease activity in rheumatoid arthritis (RA) with associated fibromyalgia (FM) before disease-modifying antirheumatic drug escalation is primordial. The goal of this study was to assess the correlation between clinical and US disease activity in RA patients with concomitant FM comparatively to RA patients without FM. Specifically, we aimed to identify the predictive factors of detection of active US-synovitis. Methods: We conducted a cross-sectional study that included patients with diagnosis of RA (ACR/EULAR 2010 criteria) with and without concomitant FM (ACR 2016). US-detected synovitis was defined and scored 0-3 using the OMERACT scoring system at the joint level for both grey-scale (GS) and Doppler power (DP). Multiple linear regression analysis performed, adjusting for clinical and demographic variables. Results: Eighty patients distributed into 40 patients in each group were recruited. No significant difference was observed between the groups in regards to mean DAS28 and the three-variables (DAS28 V3). Multiple linear regression showed that in RA+FM group US synovitis detection was positively associated with male gender (B=0.29, p=0.04) and with the DAS28 V3 (B=0.87, p=0.014), and negatively associated with the patient global assessment (PGA) (B=-0.49, p=0.004). Doppler activity was positively associated with the DAS28 V3 (B=0.51,p=0.002) and with the physician global assessment (B=0.55, p=0.02), negatively associated with the PGA (B=-0.65, p=0.005). Conclusion: Our study showed that a high DAS28 V3 seems to be significantly associated with active US-synovitis in RA patients with comorbid FM.