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].
DISCUSSION: This large-scale study demonstrates that, regardless of pain definition used, the magnitude of association between pain and other associated symptoms of fibromyalgia are similar. This supports the continued collection of both when classifying fibromyalgia but highlights that pain may not require to follow the definition outlined within the 1990ACR criteria.