Fibromyalgia (FM) is a common comorbidity in rheumatoid arthritis (RA). Recently, there were several updates for the American College of Rheumatology (ACR) FM criteria. To assess the performance of the 2016 revised ACR FM criteria in patients with RA in comparison to 1990 criteria and to study the relation to composite disease measures. This study included 130 adult RA patients fulfilling the 2010 ACR/EULAR classification criteria for RA. Patients were evaluated according to 2016 and 1990 ACR criteria for FM. Kappa agreement between the two criteria was determined. Spearman's correlation between the polysymptomatic distress scale (PSD) and selected variables including disease activity score-28 with erythrocyte sedimentation rate (DAS-28 ESR), clinical disease activity index (CDAI), patient global assessment (PGA), and visual analogue scale (VAS) for pain was evaluated. Of the 130 RA patients, 52 patients (40%) satisfied the 2016 criteria and 40 (31.5%) the 1990 criteria. The Kappa agreement between the two criteria was 0.733. RA patients with FM had higher DAS28-ESR, CDAI, PGA, and VAS compared with those without FM. A significant positive correlation was found between the polysymptomatic Distress scale (PSD) and DAS28-ESR, CDAI, and PGA (rs 0.481, 0.516, 0.511, respectively, P < 0.001). FM coexists in a substantial number of RA patients according to the 2016 revised criteria and associated with high composite disease activity measures. Therefore, assessment of FM should be considered in RA patients with persistently high disease activity.
Keywords: Fibromyalgia; Polysymptomatic distress; Prevalence; Rheumatoid arthritis.