Therapist adherence in the strong without anorexia nervosa (SWAN) study: A randomized controlled trial of three treatments for adults with anorexia nervosa.

Louise J Andony,Anthea Fursland,Elaine Tay,Susan M Byrne,Stephen Touyz,Tracey D Wade,David M Erceg‐Hurn,Karina L Allen,Ulrike H Schmidt,Virginia V.W Mcintosh,Ross D Crosby,Phillipa Hay,Christopher G Fairburn,Janet Treasure

doi:10.1002/eat.22455

Abstract

ObjectiveTo develop a psychotherapy rating scale to measure therapist adherence in the Strong Without Anorexia Nervosa (SWAN) study, a multi-center randomized controlled trial comparing three different psychological treatments for adults with anorexia nervosa. The three treatments under investigation were Enhanced Cognitive Behavioural Therapy (CBT-E), the Maudsley Anorexia Nervosa Treatment for Adults (MANTRA), and Specialist Supportive Clinical Management (SSCM).MethodThe SWAN Psychotherapy Rating Scale (SWAN-PRS) was developed, after consultation with the developers of the treatments, and refined. Using the SWAN-PRS, two independent raters initially rated 48 audiotapes of treatment sessions to yield inter-rater reliability data. One rater proceeded to rate a total of 98 audiotapes from 64 trial participants.ResultsThe SWAN-PRS demonstrated sound psychometric properties, and was considered a reliable measure of therapist adherence. The three treatments were highly distinguishable by independent raters, with therapists demonstrating significantly more behaviors consistent with the actual allocated treatment compared to the other two treatment modalities. There were no significant site differences in therapist adherence observed.DiscussionThe findings provide support for the internal validity of the SWAN study. The SWAN-PRS was deemed suitable for use in other trials involving CBT-E, MANTRA, or SSCM. © 2015 The Authors. International Journal of Eating Disorders Published by Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:1170–1175)

Highlights

In clinical trials, measuring the extent to which therapists implement treatments in accordance with their respective protocols is essential, in order for conclusions regarding treatment efficacy to be confidently determined.[1,2] Assessing therapist adherence provides an indication whether treatments under investigation can be differentiated.[2,3] Therapist adherence is commonly measured by reviewing recordings of therapy sessions, and rating whether core treatment components are observed using a suitable rating scale
The Strong Without Anorexia Nervosa (SWAN)-PRS was deemed suitable for use in other trials involving Cognitive Behavioural Therapy (CBT-E), Maudsley Anorexia Nervosa Treatment for Adults (MANTRA), or Specialist Supportive Clinical Management (SSCM)
The current study examined therapist adherence in the Strong Without Anorexia Nervosa (SWAN) study, a multi-center randomized clinical trials (RCT) comparing three different psychological treatments for adults with AN10: Enhanced Cognitive Behavioural Therapy (CBTE)[11]; Maudsley Model of Anorexia Nervosa Treatment for Adults (MANTRA)[12,13]; and SSCM.[14]

Summary

Results

Principal Axis Factor Analysis with oblique rotation was used to examine the underlying factor structure of the SWAN-PRS to allow robust, treatment-specific subscales to be determined. There was a significant overall difference found between allocated treatment groups on the CBT-E (F(2) 5 97.68, p < .001), MANTRA (F(2) 5 41.50, p 5 .001), SSCM (F(2) 5 57.68, p < .001), and Non-specific (F(2) 5 7.58, p < .05) subscales. Fisher’s Exact tests indicated that there were no significant differences in overall adherence between sites (p 5 .52), nor for CBT-E (p 5 .99), MANTRA (p 5 .36) or SSCM, (p 5 .61), when considered separately. Differences between sites in Non-Specifics subscale scores F(2) 5 0.26, p 5 .08

Discussion

Introduction

Participants