Objectives Aiming to assess the ASAS criteria for Spondyloarthritis (SpAs) in patients with Fibromyalgia (FM) we applied all items of the ASAS criteria (for both axial and peripheral disease) to 84 patients with FM.
Methods Patients with FM attending regular out patients clinics were assessed clinically by physician and given questionnaire with FM indices. Routine blood tests obtained and radiographic evaluation to exclude other diseases. individual item of Inflammatory back pain (IBP) criteria and of the ASAS criteria were also applied. Sensitivity and specificity tests have been calculated.
Results A total of 84 patients (M:F = 5:79) were assessed. They had a mean age of 47.3 years (y) (sd ± 11.2), mean age of symptom onset of 33 y (± 11.8) and mean age of diagnosis 41.9 (±10). The mean CRP of the group was 6.7 (sd ± 4). FM patients fulfilled both 1990 (tender point evaluation) and 2011 criteria. When items from the ASAS criteria were applied to the patients with FM, 6 patients (all females) had more than 1 of the items seen in the ASAS criteria (7.1%). More specifically, 6 patients had back pain onset below the age of 45 y of age and lasting for more than 3 months. Five out of 6 were positive for IBP criteria, 3 patients were HLAB27 (+), 3 patients had good response to NSAIDs, 3 patients had positive Fx of SpA (2 of Psoriasis, 1 of Crohn's disease) 2 patients had elevated CRP and 2 patients had confirmed enthesitis by ultrasound.
From those patients fulfilling the ASAS criteria for SpAs, 3 patients fulfilled criteria for axial disease, 3 fulfilled criteria for peripheral disease and 1 patient fulfilled the criteria for both axial and peripheral disease. Upon scrutinized the history and clinical evaluation 2 patients have subsequently classified as SpA while the other 4 although they could be classified as SpA they still remained under the FM umbrella requiring follow up evaluation.
The specificity and sensitivity for the ASAS criteria among FM patients have been calculated which showed a sensitivity of 2% and a specificity of 91.7% for the ASAS criteria. The positive predictive value showed to be 25% while the negative predictive value was 48%.
Conclusions Although IBP is commonly seen in patients with FM the ASAS criteria for SpAs showed low sensitivity and high specificity among FM patients which supports their discriminatory capacity among patients with these diseases.
Disclosure of Interest : None declared