title: Cost-effectiveness of blended vs. face-to-face cognitive behavioural therapy for severe anxiety disorders: study protocol of a randomized controlled trial.
abstract: BACKGROUND
  Anxiety disorders are among the most prevalent psychiatric conditions, and are associated with poor quality of life and substantial economic burden. Cognitive behavioural therapy is an effective treatment to reduce anxiety symptoms, but is also costly and labour intensive. Cost-effectiveness could possibly be improved by delivering cognitive behavioural therapy in a blended format, where face-to-face sessions are partially replaced by online sessions. The aim of this trial is to determine the cost-effectiveness of blended cognitive behavioural therapy for adults with anxiety disorders, i.e. panic disorder, social phobia or generalized anxiety disorder, in specialized mental health care settings compared to face-to-face cognitive behavioural therapy. In this paper, we present the study protocol. It is hypothesized that blended cognitive behavioural therapy for anxiety disorders is clinically as effective as face-to-face cognitive behavioural therapy, but that intervention costs may be reduced. We thus hypothesize that blended cognitive behavioural therapy is more cost-effective than face-to-face cognitive behavioural therapy.
  
  
  METHODS
  In a randomised controlled equivalence trial 156 patients will be included (n = 78 in blended cognitive behavioural therapy, n = 78 in face-to-face cognitive behavioural therapy) based on a power of 0.80, calculated by using a formula to estimate the power of a cost-effectiveness analysis: [Formula: see text]. Measurements will take place at baseline, midway treatment (7 weeks), immediately after treatment (15 weeks) and 12-month follow-up. At baseline a diagnostic interview will be administered. Primary clinical outcomes are changes in anxiety symptom severity as measured with the Beck Anxiety Inventory. An incremental cost-effectiveness ratio will be calculated to obtain the costs per quality-adjusted life years (QALYs) measured by the EQ-5D (5-level version). Health-economic outcomes will be explored from a societal and health care perspective.
  
  
  CONCLUSIONS
  This trial will be one of the first to provide information on the cost-effectiveness of blended cognitive behavioural therapy for anxiety disorders in routine specialized mental health care settings, both from a societal and a health care perspective.
  
  
  BACKGROUND
  Netherlands Trial Register NTR4912. Registered 13 November 2014.
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. g.a.romijn@vu.nl.
authors.forename: Geke
authors.initials: G
authors.lastname: Romijn
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. h.riper@vu.nl.|EMGO Institute for Health Care and Research, VU University Medical Centre, Van der Boechorststraat 7, BT 1081, Amsterdam, The Netherlands. h.riper@vu.nl.|Telepsychiatry Unit, Southern Denmark University, Campusvej 55, DK 5230, Odense M, Denmark. h.riper@vu.nl.
authors.forename: Heleen
authors.initials: H
authors.lastname: Riper
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. r.n.kok@vu.nl.|National Institute for Mental Health Research, The Australian National University, Building 63 Eggleston Road, Acton, ACT 2601, Australia. r.n.kok@vu.nl.
authors.forename: Robin
authors.initials: R
authors.lastname: Kok
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. t.donker@vu.nl.|EMGO Institute for Health Care and Research, VU University Medical Centre, Van der Boechorststraat 7, BT 1081, Amsterdam, The Netherlands. t.donker@vu.nl.
authors.forename: Tara
authors.initials: T
authors.lastname: Donker
authors.affiliation: Institute for Medical Technology Assessment (iMTA), Erasmus University, PO box 1738, Rotterdam, The Netherlands. goorden@bmg.eur.nl.
authors.forename: Maartje
authors.initials: M
authors.lastname: Goorden
authors.affiliation: Institute for Medical Technology Assessment (iMTA), Erasmus University, PO box 1738, Rotterdam, The Netherlands. hakaart@bmg.eur.nl.
authors.forename: Leona Hakkaart
authors.initials: LH
authors.lastname: van Roijen
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. l.c.kooistra@vu.nl.|EMGO Institute for Health Care and Research, VU University Medical Centre, Van der Boechorststraat 7, BT 1081, Amsterdam, The Netherlands. l.c.kooistra@vu.nl.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kooistra
authors.affiliation: EMGO Institute for Health Care and Research, VU University Medical Centre, Van der Boechorststraat 7, BT 1081, Amsterdam, The Netherlands. t.vanbalkom@ggzingeest.nl.|Department of Psychiatry, VU University Medical Centre and GGZ inGeest, P.O. Box 7057, Amsterdam, MB 1007, The Netherlands. t.vanbalkom@ggzingeest.nl.
authors.forename: Anton
authors.initials: A
authors.lastname: van Balkom
authors.affiliation: Faculty of Behavioural and Movement Sciences, Department of Clinical Psychology, VU University Amsterdam, Van der Boechorststraat 1, BT 1081, Amsterdam, The Netherlands. j.koning@propersona.nl.|Psychiatric centre Pro Persona, Siependdaallaan 3, 4003 LE, Tiel, The Netherlands. j.koning@propersona.nl.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Koning
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000191:economics* / Q000628:therapy*; D015928:Cognitive Behavioral Therapy / Q000191:economics* / Q000379:methods; D003362:Cost-Benefit Analysis / Q000379:methods; D003695:Delivery of Health Care / Q000191:economics; D005260:Female; D006801:Humans; D007406:Interview, Psychological / Q000379:methods; D009426:Netherlands; D009819:Office Visits / Q000191:economics* / Q000706:statistics & numerical data; D016584:Panic Disorder / Q000191:economics / Q000628:therapy; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D016896:Treatment Outcome; D055815:Young Adult