The Canadian Healthy Life Trajectories Initiative (HeLTI) Trial: a study protocol for monitoring fidelity of a preconception-lifestyle behaviour intervention

Background In evaluating technology-based behaviour change interventions, it is increasingly important to have a monitoring plan for intervention fidelity. It is important to maintain intervention fidelity to ensure that the theory-based intervention that is being tested is what causes the observed changes, particularly for eHealth behaviour change interventions. In this protocol, we outline the intervention fidelity and monitoring protocol for Healthy Life Trajectory Initiative (HeLTI) Canada, a randomized controlled trial evaluating the effect of a preconception-early childhood technology-based intervention delivered by public health nurses among pregnancy-planning women and their partners to optimize child growth and development. Methods The HeLTI Canada fidelity protocol is based on the National Institutes of Health Behaviour Change Consortium (NIH BCC) Treatment Fidelity Framework, outlining the following components of intervention fidelity: study design, provider training, intervention delivery, intervention receipt, and intervention enactment. The intervention fidelity components and associated monitoring strategies were developed to align with the HeLTI Canada approach. Strategies for intervention fidelity monitoring include a pre-post written evaluation of training, standardization of provider training, use and monitoring of activity logs, and intervention session checklists. Possible challenges to intervention fidelity include provider turnover due to the length of the trial and lack of ability to directly monitor participant behaviour change in real-life settings. Details about intervention fidelity monitoring are provided in detail. The study launched in January 2021 and is currently recruiting. Discussion Using the NIH BCC Treatment Fidelity Framework, HeLTI Canada has a robust framework for monitoring and reporting intervention fidelity to improve intervention validity, ability to assess intervention effectiveness, and transparency. Trial registration ISRCN ISRCTN13308752 . Registered on February 29, 2019.