Background Aiming to assess whether Inflammatory back pain (IBP) criteria are met by patients with Fibromyalgia (FM) and which items from those used in IBP criteria offer best discriminatory ability between IBP and FM a total of 63 patients (M:F=5:58) fulfilling criteria for Fibromyalgia have been assessed.
Methods All 3 sets of existing criteria for IBP (Calin, Berlin, ASAS) were applied to patients with FM. Clinical data on FM obtained on 4 different 10 cm VAS scales (10=worse possible) i.e pain, fatigue, well being past week (wbpw) sleep quality, in addition to validated questionnaires such as the fibro-fatigue scale (range 0-90), the Rotterdam scale[(range 30-120; (120 worse possible)] and ability to perform activities over past week [(range 8-32); (8=unable to perform)].
Results From 63 patients (M:F=5: 58) 3 patients (all females) fulfilled criteria for non radiologic axial Spondyloarthritis and excluded from the analysis. The remaining 60 patients had a mean age of 47.8 (SD ± 11.2; range 20-73); age of symptom onset at 34.6 (±12.2) age at diagnosis at 42 (±10.1). Scores were: FM pain =8.9 (±1.2); FM fatigue =8.5 (±1.5); Fibro-fatigue =52.6 (±13.6); sleep quality =8.5 (± 1.2); Rotterdam scale =78.09 (±14.3); activities =20.4 (±5.8), wbpw=8.7 (±1.1).
Among IBP criteria applied to patients with FM, the ASAS criteria for IBP were fulfilled by a total of 5 FM patients (18%), followed by Calin (61%) followed by the Berlin criteria (74%).
Looking at individuals items included in the IBP criteria seen in FM patients, “morning stiffness” (included in Calin and Berlin but not ASAS) and “duration of back pain for more than 3 months” (included in Calin) occurred in 96.6% and 96.4% of FM patients respectively. “Insidious onset of back pain" (included in Calin, ASAS) identified in 82% of the patients, “ge of onset of <40 years” (Calin, ASAS) identified in 68% of patients, “Alternating buttock pain” (Berlin), “awaking 2nd half of the night” (Berlin)and “pain at night with improvement upon getting up” (ASAS) were identified in nearly half (50%) of the FM patients.
“Pain improved by exercise” and “pain not improved by rest” showed to be less frequently occurring among FM patients (25%) suggesting that this item provides better discriminatory ability among the items used to define IBP and it can potentially be used to differentiate between IBP and FM.
Conclusions The ASAS criteria for IBP better discriminate SpAs from Fibromyalgia. From the items included in all 3 sets of the criteria, morning stiffness and back pain duration of more than 3 months is seen in nearly all of the FM patients. Pain improvement by exercise (included in all 3 criteria) but not by rest (ASAS, Berlin) better discriminate FM from conditions manifested by IBP.
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Disclosure of Interest : None declared