title: The comparative burden of mild, moderate and severe fibromyalgia: results from a cross-sectional survey in the United States.
abstract: BACKGROUND
  Fibromyalgia (FM) is characterized by chronic, widespread pain, fatigue, and other symptoms; yet few studies have comprehensively assessed its humanistic burden. This observational study evaluates the impact of FM severity on patients' symptoms, health-related quality of life (HRQoL), and productivity in the United States.
  
  
  METHODS
  203 FM subjects were recruited from 20 physician offices. Subjects completed a questionnaire including the EuroQol 5D (EQ-5D), Fibromyalgia Impact Questionnaire (FIQ), Multidimensional Assessment of Fatigue (MAF), Medical Outcomes Study Sleep Scale (MOS-SS), and Hospital Anxiety and Depression Scale (HADS) and questions about demographics, pain and other symptoms, HRQoL and productivity. FIQ total scores were used to define FM severity, with 0- < 39, 39- < 59, and 59-100, representing mild, moderate, and severe FM, respectively. Sites recorded subjects' clinical characteristics and FM treatment on case report forms using medical records. Summary statistics were calculated for continuous variables and frequency distributions for categorical variables. Differences across FM severity groups were evaluated using the Kruskal-Wallis or Chi-square tests. Statistical significance was evaluated at the 0.05 level.
  
  
  RESULTS
  Mean (SD) age was 47.9 (10.9); 95% were female. Most (92%) were prescribed medication for FM; 24% and 66% reported moderate and severe FM, respectively. Mean (SD) scores were: 6.3 (2.1) for pain intensity; 0.35 (0.35) for EQ-5D; 30.7 (14.2) for MAF; 57.5 (18.4) for MOS-SS Sleep Problems Index; 10.2 (4.8) for HADS anxiety and 9.4 (4.4) for HADS depression. Subjects with worse FM severity reported significantly increased pain severity, HRQoL, fatigue, sleep disturbance, anxiety and depression (p < 0.001). Overall, 50% of subjects reported some disruption in their employment due to FM; this differed across severity levels (p < 0.001). Employed subjects missed a mean (SD) of 1.8 (3.9) workdays during the past 4 weeks; this also differed across severity levels (p = 0.03).
  
  
  CONCLUSIONS
  FM imposes a substantial humanistic burden on patients in the United States, and leads to substantial productivity loss, despite treatment. This burden is higher among subjects with worse FM severity.
authors.affiliation: Health Economics and Outcomes Research, Covance Market Access Services Inc., Gaithersburg, MD, USA. Caroline.Schaefer@covance.com
authors.forename: Caroline
authors.initials: C
authors.lastname: Schaefer
authors.forename: Arthi
authors.initials: A
authors.lastname: Chandran
authors.forename: Meghan
authors.initials: M
authors.lastname: Hufstader
authors.forename: Rebecca
authors.initials: R
authors.lastname: Baik
authors.forename: Michael
authors.initials: M
authors.lastname: McNett
authors.forename: Don
authors.initials: D
authors.lastname: Goldenberg
authors.forename: Robert
authors.initials: R
authors.lastname: Gerwin
authors.forename: Gergana
authors.initials: G
authors.lastname: Zlateva
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D003710:Demography; D003866:Depressive Disorder / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D005221:Fatigue / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D005260:Female; D005356:Fibromyalgia / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology*; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011788:Quality of Life; D012720:Severity of Illness Index; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology