title: Cost of illness and illness perceptions in patients with fibromyalgia.
abstract: OBJECTIVE
  The disease impact and economic burden of fibromyalgia (FM) are high for patients and society at large. Knowing potential determinants of economic costs may help in reducing this burden. Cognitive appraisals (perceptions) of the illness could affect costs. The present study estimated costs of illness in FM and examined the association between these costs and illness perceptions.
  
  
  METHODS
  Questionnaire data of FM severity (FIQ), illness perceptions (IPQ-R-FM), productivity losses (SF-HLQ) and health care use were collected in a cohort of patients with FM. Costs were calculated and dichotomised (median split). Univariate and hierarchic logistic regression models examined the unique association of each illness perception with 1) health care costs and 2) costs of productivity losses. Covariates were FM severity, comorbidity and other illness perceptions.
  
  
  RESULTS
  280 patients participated: 95% female, mean age 42 (SD=12) years. Annualised costs of FM per patient were €2944 for health care, and €5731 for productivity losses. In multivariate analyses, a higher disease impact (FIQ) and two of seven illness perceptions (IPQ-R-FM) were associated with high health care costs: 1) high scores on 'cyclical timeline' reflecting a fluctuating, unpredictable course and 2) low scores on 'emotional representations', thus not perceiving a connection between fibromyalgia and emotions. None of the variables was associated with productivity losses.
  
  
  CONCLUSIONS
  Our study indicates that perceiving a fluctuating course and low emotional representation, which perhaps reflects somatic fixation, are associated with health care costs in FM. Future studies should examine whether targeting these illness perceptions results in reduction of costs.
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands. v.vervoort@maartenskliniek.nl.
authors.forename: Vera M
authors.initials: VM
authors.lastname: Vervoort
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Johanna E
authors.initials: JE
authors.lastname: Vriezekolk
authors.affiliation: Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Tim C
authors.initials: TC
authors.lastname: Olde Hartman
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Hans A
authors.initials: HA
authors.lastname: Cats
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Toon
authors.initials: T
authors.lastname: van Helmond
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Woerden, The Netherlands.
authors.forename: Willemijn H
authors.initials: WH
authors.lastname: van der Laan
authors.affiliation: Department of Clinical and Health Psychology, Utrecht University; and Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, The Netherlands.
authors.forename: Rinie
authors.initials: R
authors.lastname: Geenen
authors.affiliation: Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Cornelia H
authors.initials: CH
authors.lastname: van den Ende
mesh_terms: D000328:Adult; D017281:Cost of Illness; D059026:Diagnostic Self Evaluation; D005260:Female; D005356:Fibromyalgia / Q000191:economics / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011788:Quality of Life; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D013223:Statistics as Topic; D011795:Surveys and Questionnaires