Hawkes Rhiannon E, Miles Lisa M, Bower Peter, Cotterill Sarah, French David P
Manchester Centre of Health Psychology, Division of Psychology and Mental Health, University of Manchester, Manchester, UK.
Division of Population Health, Health Services Research & Primary Care, University of Manchester, Manchester, UK.
Health Psychol Behav Med. 2022 May 23;10(1):498-513. doi: 10.1080/21642850.2022.2077205. eCollection 2022.
Health services interventions are typically more effective in randomised controlled trials than in routine healthcare. One explanation for this 'voltage drop', i.e. reduction in effectiveness, is a reduction in intervention fidelity, i.e. the extent to which a programme is implemented as intended. This article discusses how to optimise intervention fidelity in nationally implemented behaviour change programmes, using as an exemplar the National Health Service Diabetes Prevention Programme (NHS-DPP); a behaviour change intervention for adults in England at increased risk of developing Type 2 diabetes, delivered by four independent provider organisations. We summarise key findings from a thorough fidelity evaluation of the NHS-DPP assessing design (whether programme plans were in accordance with the evidence base), training (of staff to deliver key intervention components), delivery (of key intervention components), receipt (participant understanding of intervention content), and highlight lessons learned for the implementation of other large-scale programmes.
NHS-DPP providers delivered the majority of behaviour change content specified in their programme designs. However, a drift in fidelity was apparent at multiple points: from the evidence base, during programme commissioning, and on to providers' programme designs. A lack of clear theoretical rationale for the intervention contents was apparent in design, training, and delivery. Our evaluation suggests that many fidelity issues may have been less prevalent if there was a clear underpinning theory from the outset.
We provide recommendations to enhance fidelity of nationally implemented behaviour change programmes. The involvement of a behaviour change specialist in clarifying the theory of change would minimise drift of key intervention content. Further, as loss of fidelity appears notable at the design stage, this should be given particular attention. Based on these recommendations, we describe examples of how we have worked with commissioners of the NHS-DPP to enhance fidelity of the next roll-out of the programme.
卫生服务干预措施在随机对照试验中通常比在常规医疗保健中更有效。对于这种“电压降”，即效果降低的一种解释是干预保真度降低，也就是一个项目按预期实施的程度。本文以英国国家医疗服务体系糖尿病预防计划（NHS - DPP）为例，探讨如何在全国实施的行为改变计划中优化干预保真度；该计划是针对英国有患2型糖尿病风险增加的成年人的行为改变干预措施，由四个独立的提供机构实施。我们总结了对NHS - DPP进行全面保真度评估的主要发现，评估内容包括设计（项目计划是否符合证据基础）、培训（工作人员实施关键干预组成部分的培训）、实施（关键干预组成部分的实施）、接受情况（参与者对干预内容的理解），并强调了在实施其他大规模项目中吸取的经验教训。
NHS - DPP的提供机构实施了其项目设计中规定的大部分行为改变内容。然而，在多个环节都明显存在保真度的偏差：从证据基础、项目委托阶段到提供机构的项目设计。在设计、培训和实施过程中，干预内容缺乏明确的理论依据是显而易见的。我们的评估表明，如果从一开始就有明确的基础理论，许多保真度问题可能就不会那么普遍。
我们提供了提高全国实施的行为改变计划保真度的建议。让行为改变专家参与阐明改变理论将使关键干预内容的偏差最小化。此外，由于保真度在设计阶段的损失似乎很明显，应特别予以关注。基于这些建议，我们描述了我们如何与NHS - DPP的委托方合作以提高该计划下一次推广的保真度的示例。
