title: Posttreatment attrition and its predictors, attrition bias, and treatment efficacy of the anxiety online programs.
abstract: BACKGROUND
  Although relatively new, the field of e-mental health is becoming more popular with more attention given to researching its various aspects. However, there are many areas that still need further research, especially identifying attrition predictors at various phases of assessment and treatment delivery.
  
  
  OBJECTIVE
  The present study identified the predictors of posttreatment assessment completers based on 24 pre- and posttreatment demographic and personal variables and 1 treatment variable, their impact on attrition bias, and the efficacy of the 5 fully automated self-help anxiety treatment programs for generalized anxiety disorder (GAD), social anxiety disorder (SAD), panic disorder with or without agoraphobia (PD/A), obsessive-compulsive disorder (OCD), and posttraumatic stress disorder (PTSD).
  
  
  METHODS
  A complex algorithm was used to diagnose participants' mental disorders based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision; DSM-IV-TR). Those who received a primary or secondary diagnosis of 1 of 5 anxiety disorders were offered an online 12-week disorder-specific treatment program. A total of 3199 individuals did not formally drop out of the 12-week treatment cycle, whereas 142 individuals formally dropped out. However, only 347 participants who completed their treatment cycle also completed the posttreatment assessment measures. Based on these measures, predictors of attrition were identified and attrition bias was examined. The efficacy of the 5 treatment programs was assessed based on anxiety-specific severity scores and 5 additional treatment outcome measures.
  
  
  RESULTS
  On average, completers of posttreatment assessment measures were more likely to be seeking self-help online programs; have heard about the program from traditional media or from family and friends; were receiving mental health assistance; were more likely to learn best by reading, hearing and doing; had a lower pretreatment Kessler-6 total score; and were older in age. Predicted probabilities resulting from these attrition variables displayed no significant attrition bias using Heckman's method and thus allowing for the use of completer analysis. Six treatment outcome measures (Kessler-6 total score, number of diagnosed disorders, self-confidence in managing mental health issues, quality of life, and the corresponding pre- and posttreatment severity for each program-specific anxiety disorder and for major depressive episode) were used to assess the efficacy of the 5 anxiety treatment programs. Repeated measures MANOVA revealed a significant multivariate time effect for all treatment outcome measures for each treatment program. Follow-up repeated measures ANOVAs revealed significant improvements on all 6 treatment outcome measures for GAD and PTSD, 5 treatment outcome measures were significant for SAD and PD/A, and 4 treatment outcome measures were significant for OCD.
  
  
  CONCLUSIONS
  Results identified predictors of posttreatment assessment completers and provided further support for the efficacy of self-help online treatment programs for the 5 anxiety disorders.
  
  
  BACKGROUND
  Australian and New Zealand Clinical Trials Registry ACTRN121611000704998; http://www.anzctr.org.au/trial_view.aspx?ID=336143 (Archived by WebCite at http://www.webcitation.org/618r3wvOG).
authors.affiliation: School of Health Sciences, Swinburne University of Technology, Hawthorn, Australia. aalasadi@gprc.ab.ca.
authors.forename: Ali M
authors.identifier: http://orcid.org/0000-0003-2256-1290
authors.initials: AM
authors.lastname: Al-Asadi
authors.forename: Britt
authors.identifier: http://orcid.org/0000-0003-2912-8043
authors.initials: B
authors.lastname: Klein
authors.forename: Denny
authors.identifier: http://orcid.org/0000-0002-9902-0858
authors.initials: D
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000523:psychology* / Q000628:therapy*; D015982:Bias; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D017063:Outcome Assessment, Health Care; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D055815:Young Adult
keywords: Internet interventions; Web treatment; cognitive behavioral therapy; e-mental health; fully automated; generalized anxiety disorder; obsessive compulsive disorder; online therapy; posttreatment attrition; posttreatment predictors; self-help; treatment efficacy