Abstract Background/Aims Fibromyalgia (FM), the prototypical central sensitivity syndrome, affects 21% of patients with established inflammatory arthritis (IA) - about tenfold higher than in the general population. It is often assumed that FM features emerge progressively over the disease course. However, we recently showed that features of centrally mediated pain are present at diagnosis. To validate these findings, we examined FM prevalence and clinical characteristics in a larger IA cohort from the same clinical centre. Methods All new patients at Guy’sHospital, London rheumatology clinic (February to May 2019) were invited tocomplete a digital pre-appointment questionnaire. Assessments included: demographics,2016 FM criteria (widespread pain index WPI and symptom severity scoreSSS), depression (PHQ8), anxiety (GAD7) and somatic symptoms (PHQ15). Aretrospective analysis was performed to determine the prevalence of FM amongpatients who were subsequently diagnosed with IA. Clinical characteristics werecompared between groups using 2-sided t-test or χ² tests. Associations betweeninflammatory markers (CRP, ESR) and FM severity were tested with linearregression adjusted for age and gender. Results Of 891 referrals, 226 patients were diagnosed with IA (mean age 45 ± 15 years; 56% female). Among these, 118 (53%) reported WPI ≥7, 101 (45%) fulfilled FM criteria and 197 (88%) reported chronic pain. Psychological distress was common, with at least moderate levels of depression in 31%, anxiety in 18%, and somatic symptoms in 39%. There were more females and higher scores for depression, anxiety and somatic symptoms in those fulfilling fibromyalgia criteria (Table 1). Neither CRP or ESR was associated with FM severity (CRP: β = 0.013, 95% CI -0.031 to 0.057, p = 0.57, ESR: β = 0.009, 95% CI -0.044 to 0.062, p = 0.73), suggesting widespread pain is not driven by inflammatory burden. Conclusion FM rates in this early IA cohort were high, with high levels of psychological distress and chronic pain preceding the first clinic appointment. These findings may reflect a background population with high rates of primary fibromyalgia unrelated to IA, the impact of chronic inflammation triggering central pain mechanisms, and/or limitations of the patient-reported 2016 FM criteria, which may be overly inclusive. Disclosure Z. Rutter-Locher: Grants/research support; NIHR301674. N. Arumalla: None. L. Taams: None. K. Bannister: None. T. Garrood: None. B. Kirkham: None.
Rutter-Locher et al. (Wed,) studied this question.