title: Cognitive behaviour therapy for chronic fatigue syndrome: Differences in treatment outcome between a tertiary treatment centre in the United Kingdom and the Netherlands.
abstract: Cognitive behaviour therapy (CBT) reduces fatigue and disability in chronic fatigue syndrome (CFS). However, outcomes vary between studies, possibly because of differences in patient characteristics, treatment protocols, diagnostic criteria and outcome measures. The objective was to compare outcomes after CBT in tertiary treatment centres in the Netherlands (NL) and the United Kingdom (UK), using different treatment protocols but identical outcome measures, while controlling for differences in patient characteristics and diagnostic criteria.
  
  
  
  Consecutively referred CFS patients who received CBT were included (NL: n=293, UK: n=163). Uncontrolled effect sizes for improvement in fatigue (Chalder Fatigue Questionnaire), physical functioning (SF-36 physical functioning subscale) and social functioning (Work and Social Adjustment Scale) were compared. Multiple regression analysis was used to examine whether patient differences explained outcome differences between centres.
  
  
  
  Effect sizes differed between centres for fatigue (Cohen's D NL=1.74, 95% CI=1.52-1.95; UK=0.99, CI=0.73-1.25), physical functioning (NL=0.99, CI=0.81-1.18; UK=0.33, CI=0.08-0.58) and social functioning (NL=1.47, CI=1.26-1.69; UK=0.61, CI=0.35-0.86). Patients in the UK had worse physical functioning at baseline and there were minor demographic differences. These could not explain differences in centre outcome.
  
  
  
  Effectiveness of CBT differed between treatment centres. Differences in treatment protocols may explain this and should be investigated to help further improve outcomes.
authors.affiliation: Expert Centre for Chronic Fatigue, Radboud University Medical Center, Reinier Postlaan 4 (916), 6525GC Nijmegen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Worm-Smeitink
authors.affiliation: Expert Centre for Chronic Fatigue, Radboud University Medical Center, Reinier Postlaan 4 (916), 6525GC Nijmegen, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Nikolaus
authors.affiliation: Biostatistics Department, Institute of Psychiatry, Psychology & Neuroscience, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom.
authors.forename: K
authors.initials: K
authors.lastname: Goldsmith
authors.affiliation: Expert Centre for Chronic Fatigue, Radboud University Medical Center, Reinier Postlaan 4 (916), 6525GC Nijmegen, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Wiborg
authors.affiliation: Chronic Fatigue Research and Treatment Unit, South London and Maudsley NHS Foundation Trust, Mapother House, Maudsley Hospital, Denmark Hill, London SE5 8AZ, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Ali
authors.affiliation: Expert Centre for Chronic Fatigue, Radboud University Medical Center, Reinier Postlaan 4 (916), 6525GC Nijmegen, The Netherlands; Department of Medical Psychology, Academic Medical Centre (AMC), University of Amsterdam, Amsterdam, The Netherlands. Electronic address: hans.knoop@amc.uva.nl.
authors.forename: H
authors.initials: H
authors.lastname: Knoop
authors.affiliation: Department of Psychological Medicine, King's College London, Weston Education Centre, Cutcombe Road, London SE5 9RJ, United Kingdom; Chronic Fatigue Research and Treatment Unit, South London and Maudsley NHS Foundation Trust, Mapother House, Maudsley Hospital, Denmark Hill, London SE5 8AZ, United Kingdom.
authors.forename: T
authors.initials: T
authors.lastname: Chalder
mesh_terms: D000328:Adult; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D006233:Persons with Disabilities / Q000523:psychology; D015673:Fatigue Syndrome, Chronic / Q000453:epidemiology / Q000523:psychology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011795:Surveys and Questionnaires; D062606:Tertiary Care Centers; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology
keywords: Chronic fatigue syndrome; Cognitive behaviour therapy; Outcome prediction; Treatment outcome; Treatment protocols