Changes in a Digital Type 2 Diabetes Self-management Intervention During National Rollout: Mixed Methods Study of Fidelity

Background: "Healthy Living for People with type 2 Diabetes (HeLP-Diabetes)" was a theory-based digital self-management intervention for people with type 2 diabetes mellitus that encouraged behavior change using behavior change techniques (BCTs) and promoted self-management. HeLP-Diabetes was effective in reducing HbA1c levels in a randomized controlled trial (RCT). National Health Service (NHS) England commissioned a national rollout of HeLP-Diabetes in routine care (now called "Healthy Living"). Healthy Living presents a unique opportunity to examine the fidelity of the national rollout of an intervention originally tested in an RCT. Objective: This research aimed to describe the Healthy Living BCT and self-management content and features of intervention delivery, compare the fidelity of Healthy Living with the original HeLP-Diabetes intervention, and explain the reasons for any fidelity drift during national rollout through qualitative interviews. Methods: Content analysis of Healthy Living was conducted using 3 coding frameworks (objective 1): the BCT Taxonomy v1, a new coding framework for assessing self-management tasks, and the Template for Intervention Description and Replication. The extent to which BCTs and self-management tasks were included in Healthy Living was compared with published descriptions of HeLP-Diabetes (objective 2). Semistructured interviews were conducted with 9 stakeholders involved in the development of HeLP-Diabetes or Healthy Living to understand the reasons for any changes during national rollout (objective 3). Qualitative data were thematically analyzed using a modified framework approach. Results: The content analysis identified 43 BCTs in Healthy Living. Healthy Living included all but one of the self-regulatory BCTs ("commitment") in the original HeLP-Diabetes intervention. Healthy Living was found to address all areas of self-management (medical, emotional, and role) in line with the original HeLP-Diabetes intervention. However, 2 important changes were identified. First, facilitated access by a health care professional was not implemented; interviews revealed this was because general practices had fewer resources in comparison with the RCT. Second, Healthy Living included an additional structured web-based learning curriculum that was developed by the HeLP-Diabetes team but was not included in the original RCT; interviews revealed that this was because of changes in NHS policy that encouraged referral to structured education. Interviewees described how the service provider had to reformat the content of the original HeLP-Diabetes website to make it more usable and accessible to meet the multiple digital standards required for implementation in the NHS. Conclusions: The national rollout of Healthy Living had good fidelity to the BCT and self-management content of HeLP-Diabetes. Important changes were attributable to the challenges of scaling up a digital intervention from an RCT to a nationally implemented intervention, mainly because of fewer resources available in practice and the length of time since the RCT. This study highlights the importance of considering implementation throughout all phases of intervention development.