Clinical overlap between fibromyalgia tender points and enthesitis sites in patients with spondyloarthritis who present with inflammatory back pain.

OBJECTIVES: To assess the extent of coexistence of inflammatory back pain (IBP) with fibromyalgia (FM) features in patients with spondyloarthritis (SpA), and to assess the degree of overlap of FM tender points (TeP) and enthesitis sites (ES) in patients with SpA. METHODS: We evaluated 61 consecutive patients who presented with IBP. Anterior and posterior anatomic diagrams were used as an aid to record assessments of TeP typically seen in FM and ES. RESULTS: Of the patients assessed (n=61), 60 patients (97.9%) fulfilled criteria for IBP (male: female=17:43 (28.3%:71.7%); mean age=47.9 years (SD=11.5) and were included in the analysis. Of those who returned the questionnaire (n=47 (78.3%), 76.6% had onset of symptoms at ≤40 years (mean age=33.5±12.5 years), 87.2% had back pain of ≥3 months duration, 91.5% had morning stiffness (mean duration=70±66 minutes), and 60% showed improvement of pain with exercise. Eating disorders were reported by 21.3% of subjects, and stress was identified as a disease trigger by 40.4% of the respondents. Other symptoms related to FM were reported by 68.1% of the interviewed subjects. Of the 60 patients assessed, 18 (30%) fulfilled the clinical criteria for FM (at least 11 out of 18 TeP). Using regression analysis, a significant correlation was identified between FM TeP and ES. CONCLUSIONS: One third of patients with IBP fulfilled the criteria for FM. There is a significant degree of overlap between FM TeP and ES in patients with IBP.