Ensuring Yoga Intervention Fidelity in a Randomized Preference Trial for the Treatment of Worry in Older Adults.

Introduction: Yoga for treatment of worry in older adults is an intervention that is especially likely to translate into real-world practice. Assessing treatment fidelity improves confidence that effective interventions can be consistently applied and allows researchers to explore if any null results for effectiveness are indeed the result of a lack of intervention efficacy or lack of proper intervention implementation. Methods: This study describes treatment fidelity of a yoga intervention in a randomized preference trial that compared cognitive-behavioral therapy (CBT) and yoga for the treatment of worry, anxiety, and sleep in worried older (≥60 years) adults. Established methods for assessing treatment fidelity of CBT guided the procedure for ensuring that the yoga intervention was delivered as intended. The yoga intervention consisted of 20, 75-min, in-person, group, gentle yoga classes held twice weekly. Results: Six female instructors (mean age = 64 years) taught 660 yoga classes that were videotaped. Ten percent of these classes, stratified by instructor, were randomly selected for review. The average adherence score for yoga instructors was 6.84 (range 4-8). The average competency scores were consistently high, with an average score of 7.24 (range 6-8). Teaching content not included in the protocol occurred in 26 (38.1%) sessions and decreased over time. Observed ratings of instructor adherence were significantly related to ratings of competency. Instructor adherence was also significantly associated with lower participant attendance, but not with any of the other process or outcome measures. Conclusions: The larger range found in adherence relative to competence scores demonstrated that teaching a yoga class according to a protocol requires different skills than competently teaching a yoga class in the community, and these skills improved with feedback. These results may foster dialog between the yoga research and practice communities. Clinical Trial Registration No.: NCT02968238.