The impact of moving from a widespread to multi-site pain definition on other fibromyalgia symptoms

Objectives: The current study investigated whether associations between pain and the additional symptoms associated with fibromyalgia are different in persons with chronic widespread (CWP) compared to multi-site pain (MSP), with or without joint areas. Patients/Methods: Six studies were utilized: 1958 British birth cohort, EpiFunD, Kid LBP, MUSICIAN, SHAMA and WHEST (females) studies. MSP was defined as the presence of pain in ≥8/≥10 body sites (adults/children) indicated on 4-view body manikins; conducted firstly to include joints (+joints) and secondly without (-joints). The relationship between pain and fatigue, sleep disturbance, somatic symptoms and mood impairment, were assessed using logistic regression. Results are presented as odds ratios (OR), with 95% confidence intervals (CI). Results: There were 34,818 participants across the study populations (adults: mean age range 42-56yrs, % male 43-51 (excluding WHEST), CWP prevalence 12-17%). Amongst those reporting MSP, the proportion reporting CWP ranged between 62-76%. Amongst those reporting the symptoms associated with fibromyalgia, there was an increased likelihood of reporting pain, the magnitude of which were similar regardless of definition used. For example, within WHEST; reporting moderate/severe fatigue (Chalder fatigue scale 4-11) was associated with over a 5-fold increase in likelihood of reporting pain [CWP OR 5.2, 95%CI 3.9-6.9; MSP+joints 6.5, 5.0-8.6; MSP-joints 6.5, 4.7-9.0]