Discussion
low weight eating disorders
This pilot study is the first to develop and validate an adherence coding measure (the IE-ACF) to evaluate treatment fidelity to a novel FBT-IE treatment for adolescents with low weight eating disorders. The data demonstrated that 1) six sessions of FBT-IE can be delivered with adherence to the treatment manual in the context of an ongoing clinical trial and 2) that independent coders reliably coded sessions as adherent using our novel adherence coding tool.Inter-rater reliability was moderate to almost perfect across the study sessions (κ range 0.77–0.96), which suggests that IE-ACF is a reliable measure for evaluating therapist adherence to the FBT-IE treatment. Therapist adherence to the manual was present across the sessions (range 76–88%), while adherence to individual session items varied considerably (range 36%-100%). Across sessions, Sessions 1 and 2 demonstrated the highest inter-rater reliability, which we attribute to greater clarity in the coding items for these sessions. Two broad features of the IE-ACF likely contributed to the high levels of adherence and inter-rater reliability, namely the use of a treatment manual and binary coding. Treatment manuals reduce the variability in session content, promote treatment fidelity, and facilitate the training of therapists, ongoing supervision, and the training of adherence coders. The use of a binary coding scheme facilitated the use of objective assessments and promotes inter-rater reliability.To examine more specific factors that may have affected our outcomes, the lowest scoring items were reviewed to understand reasons for variability in adherence. The item “Did parents encourage/push child to drink more of shake during the IE exercise?” was consistently low (range: 50–70% adherence) as it proved challenging for the parents to push their child to consume the shake amidst resistance, uncertainty, and the expression of disgust. The item “Did therapist encourage parents to adopt role as ‘coach’ during the IE exercise?” was also consistently low across sessions. In delivering this treatment intervention, the therapist only used the term “coach” when the sports analogy was salient and relevant to the family. While therapists generally adhered to the treatment framework, they approached the intervention flexibly acknowledging that each family is unique and not all families identified with every metaphor. This balance of structure and flexibility reflects the general approach to the delivery of manual-based treatment in the field more broadly. We believe this item would have demonstrated greater adherence if the item assessed whether the therapist encouraged the parents to assume a supportive or authoritative role. We, therefore, calculated mean adherence per session with and without this item included (Variability in adherence to other treatment items can be attributed to different approaches by the therapist in administering therapeutic content or different interpretations by the coder in coding the items. Objective items such as “did the therapist provide the shake” had higher adherence than less objective items such as the therapists’ explanation of how to apply a skill during the week. There were also practical elements that impacted adherence, such as the therapist not having a finger trap available during the session that included the exercise utilizing it.The findings of this study should be considered in light of the primary limitation of sample size. Only 49% of total available sessions were videotaped, which may have introduced a selection bias attributable to random recording loss due to sound quality, extracting data, or uploading videos. However, all videotaped sessions with adequate audio quality were coded, which reduces the chance of a systematic bias. Additionally, data from the IE-ACF are consistent with others in the field. Perfect inter-rater reliability scores are rare, and previous studies in FBT report a wide range from poor to almost perfect inter-rater reliability scores for ratings of treatment fidelity [In summary, the psychometric properties of IE-ACF showed 80% adherence of therapists to the treatment manual and moderate and almost perfect inter-rater reliability in the coding of adherence by two trained, independent coders. Future research should examine the relationship between therapist adherence to FBT-IE and treatment outcomes.