Purpose: To evaluate the long-term effectiveness of a web-based therapist-delivered cognitive behavioral therapy (CBT) for patients with eating disorders (ED).
Methods: We used follow-up data from a randomized controlled trial that evaluated a web-based CBT on ED psychopathology and related health, compared to a waiting list control (WL) condition. As participants of the WL condition started the intervention after their waiting period, follow-up data included participants from both groups. The primary outcome was change from baseline, at 3, 6, and 12-month intervals in ED psychopathology, analyzed using mixed models for repeated measures. Secondary outcomes included body dissatisfaction, BMI, physical health, mental health, self-esteem, quality of life, and social functioning.
Results: The population comprised 212 participants in total, in three subgroups: bulimia nervosa (BN; n = 44), binge eating disorder (BED; n = 83), and ED not otherwise specified (EDNOS; n = 85). Treatment effects were sustained during follow-up, with generally large effect sizes for the reduction of ED psychopathology and body dissatisfaction, and small to moderate effect sizes for physical and mental health, self-esteem, social functioning, and quality of life. Most effects were found for all three subgroups, except for long-term improvements in self-esteem and quality of life among participants with BN and EDNOS.
Conclusion: This study showed long-term sustainability of treatment effects up to 1-year post-treatment of a web-based therapist-delivered CBT for patients with various ED.
Level of evidence: Level IV, evidence obtained from multiple time series analysis, with intervention.
Unique clinical trial number: NTR2415-Dutch Trial Registry ( http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2415 ).
Keywords: Binge eating disorder; Bulimia nervosa; Eating disorders; Long-term effectiveness; Web-based treatment; eHealth.