Common and contrasting characteristics of the chronic soft-tissue pain conditions fibromyalgia and lipedema

Objective: To examine the common and specific characteristics of fibromyalgia and lipedema, two chronic soft-tissue pain syndromes without curative therapy options. Methods: Diseases' characteristics were compared using the findings of extensive literature and the empiric data from two cohorts, both fulfilling standardized diagnostic criteria. Outcome was measured by various socio-demographics, the generic Short Form 36 (SF-36), the Fibromyalgia Severity Questionnaire (FSQ), and the 6-minute walk distance (6MWD). Empiric SF-36 data were compared to specific population-based norms and between the diagnostic groups, using standardized mean differences (SMD). Results: Female participants with fibromyalgia (n = 77) and lipedema (n = 112) showed comparable education levels and living situations. Lipedema cases were, on average, 3.9 years younger and BMI 6.3kg/m2 more obese. Women with fibromyalgia smoked more, did less sport, had more comorbidities, and worked less. Compared to the norms, health in fibromyalgia was worse than expected by SMD = -1.60 to -2.35 and in lipedema by -0.44 to -0.82 on the SF-36. The score differences between the two conditions ranged from SMD = -0.96 to -1.34 (all p < 0.001) on the SF-36 and the FSQ. For the inpatients (n = 77 fibromyalgia, n = 38 lipedema), the 6MWD was comparable (SMD = -0.09, p = 0.640). These findings were consistent with detailed data from the literature reviewed. Discussion: Fibromyalgia and lipedema share characteristics of clinical phenomenology and comorbid conditions. Disease perception is more pronounced in fibromyalgia than in lipedema, especially in social and role dysfunction, whereas the walking distance was similar for both syndromes. This difference may be explicable by limited coping skills in fibromyalgia