Background Fibromyalgia (FM) has a significant impact on health status, functional ability, and quality of life. In patients with rheumatoid arthritis (RA), concomitant FM has been reported in 15 –20% of cases. There is evidence showing that the presence of FM is associated with a significant increase in the HAQ score in patients with RA. There are controversial data regarding impact of FM on measurement of disease activity in RA patients.
Objectives The purpose of this study was to investigate the effect of FM comorbidity on disease activity measure in patient with RA.
Methods We have examined 122 (9 men, 113 women) with RA according to the ACR/EULAR (2010) criteria. Concomitant FM in RA patient was revealed by the ACR (1990) criteria. All the patients were examined by rheumatologist, assessing tender joint count (TJC), swollen joint count (SJC), and tender point count (TPC). Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were recorded. Disease activity was measured by DAS-28, which includes TJC, SJC, ESR, and patient general health by a 100 mm visual analog scale (VAS-GH), and also by the Clinical Disease Activity Index (CDAI). Functional disability was assessed by the Health Assessment Questionnaire.
Results A total of 24/122 (19.7%) patients in the investigated cohort had ≥11 tender points and met the criteria for FM. Patients with FM had higher tender joint counts, VAS-GH, DAS-28, CDAI and HAQ. Most patients with FM had high disease activity (DAS-28 ≥5.1). The same result occurred if the DAS-28 was replaced by CDAI – most FM patient where characterized as highly active. However, their swollen joint counts, ESR and CRP were similar to those without FM.
Conclusions Our findings confirm previous reports that about 20% of RA patients have concomitant FM. Presence of FM in RA patients mimics high disease activity when it calculated by DAS28 or CDAI because it is related to higher scores independently of objective evidence of RA activity.
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Disclosure of Interest None declared