Does the design of the NHS Low‐Calorie Diet Programme have fidelity to the programme specification? A documentary review of service parameters and behaviour change content in a type 2 diabetes intervention

Abstract

Background: NHS England commissioned four independent service providers to pilot low-calorie diet programmes to drive weight loss, improve glycaemia and potentially achieve remission of Type 2 Diabetes across 10 localities. Intervention fidelity might contribute to programme success. Previous research has illustrated a drift in fidelity in the design and delivery of other national diabetes programmes. Aims:(1) To describe and compare the programme designs across the four service providers; (2) To assess the fidelity of programme designs to the NHS England service specification. Methods:The NHS England service specification documents and each provider's programme design documents were double-coded for key intervention content using the Template for Intervention Description and Replication Framework and the Behaviour Change Technique (BCT) Taxonomy. Results:The four providers demonstrated fidelity to most but not all of the service parameters stipulated in the NHS England service specification. Providers included between 74% and 87% of the 23 BCTs identified in the NHS specification.Twelve of these BCTs were included by all four providers; two BCTs were consistently absent. An additional seven to 24 BCTs were included across providers. Conclusions:A loss of fidelity for some service parameters and BCTs was identified across the provider's designs; this may have important consequences for programme delivery and thus programme outcomes. Furthermore, there was a large degree of variation between providers in the presence and dosage of additional BCTs. How these findings relate to the fidelity of programme delivery and variation in programme outcomes and experiences across providers will be examined.

Diabetes prevention at scale: Narrative review of findings and lessons from the DIPLOMA evaluation of the NHS Diabetes Prevention Programme in England

“…As well as addressing gaps in evaluation and feedback seen in previous years of policy‐making, 46 the traditional challenges of independent evaluation in DIPLOMA have also highlighted key strengths of the NHS and NIHR infrastructure, in terms of national coverage and access to key data assets that have enabled the application of non‐experimental methods for evaluation. The learning from DIPLOMA provides a useful model for future evaluations of diabetes care at scale, such as the NHS Low Calorie Diet programme 47,48 …”

“…The learning from DIPLOMA provides a useful model for future evaluations of diabetes care at scale, such as the NHS Low Calorie Diet programme. 47,48…”

Understanding how self‐management education and support programmes for type 2 diabetes are expected to change behaviour: A document analysis of two programmes

“…A documentary analysis of programme materials was conducted in line with the methods employed in previous research to examine the active ingredients and expected MoAs of interventions. [17][18][19][20][21][22][23][24] Materials were sourced and selected for review and analysis in collaboration with relevant stakeholders, including programme managers and diabetes educators, to ensure that documents providing more detailed information on the content of the programmes were included in the analysis. The selected materials included the following (see Appendix S2 for an outline of the included documents):…”

“…This study provides a foundation for further research on programmes' fidelity, specifically regarding how intervention content is delivered, understood and used by participants. 18 Additionally, programmes can build on these findings to explore the extent to which the BCTs and MoAs identified influence programmes' effectiveness. Similarly, programmes can build on this study to explore the extent to which the mode of delivery of BCTs influences their effectiveness.…”

“…Notably, providers often provided limited information about the rationale for the selection of theories and constructs that informed programme's design, and the links between theoretical constructs and BCTs. [17][18][19][20] Previous reviews have primarily focused on digitally delivered interventions when examining the active ingredients of self-management interventions for type 2 diabetes. [21][22][23][24] However, limited attention has been paid to the active components of widely delivered in-person DSMES programmes.…”