Referral to the NHS Diabetes Prevention Programme and conversion from nondiabetic hyperglycaemia to type 2 diabetes mellitus in England: A matched cohort analysis.

BACKGROUND: The NHS Diabetes Prevention Programme (NDPP) is a behaviour change programme for adults who are at risk of developing type 2 diabetes mellitus (T2DM): people with raised blood glucose levels, but not in the diabetic range, diagnosed with nondiabetic hyperglycaemia (NDH). We examined the association between referral to the programme and reducing conversion of NDH to T2DM. METHODS AND FINDINGS: Cohort study of patients attending primary care in England using clinical Practice Research Datalink data from 1 April 2016 (NDPP introduction) to 31 March 2020 was used. To minimise confounding, we matched patients referred to the programme in referring practices to patients in nonreferring practices. Patients were matched based on age (≥3 years), sex, and ≥365 days of NDH diagnosis. Random-effects parametric survival models evaluated the intervention, controlling for numerous covariates. Our primary analysis was selected a priori: complete case analysis, 1-to-1 practice matching, up to 5 controls sampled with replacement. Various sensitivity analyses were conducted, including multiple imputation approaches. Analysis was adjusted for age (at index date), sex, time from NDH diagnosis to index date, BMI, HbA1c, total serum cholesterol, systolic blood pressure, diastolic blood pressure, prescription of metformin, smoking status, socioeconomic status, a diagnosis of depression, and comorbidities. A total of 18,470 patients referred to NDPP were matched to 51,331 patients not referred to NDPP in the main analysis. Mean follow-up from referral was 482.0 (SD = 317.3) and 472.4 (SD = 309.1) days, for referred to NDPP and not referred to NDPP, respectively. Baseline characteristics in the 2 groups were similar, except referred to NDPP were more likely to have higher BMI and be ever-smokers. The adjusted HR for referred to NDPP, compared to not referred to NDPP, was 0.80 (95% CI: 0.73 to 0.87) (p < 0.001). The probability of not converting to T2DM at 36 months since referral was 87.3% (95% CI: 86.5% to 88.2%) for referred to NDPP and 84.6% (95% CI: 83.9% to 85.4%) for not referred to NDPP. Associations were broadly consistent in the sensitivity analyses, but often smaller in magnitude. As this is an observational study, we cannot conclusively address causality. Other limitations include the inclusion of controls from the other 3 UK countries, data not allowing the evaluation of the association between attendance (rather than referral) and conversion. CONCLUSIONS: The NDPP was associated with reduced conversion rates from NDH to T2DM. Although we observed smaller associations with risk reduction, compared to what has been observed in RCTs, this is unsurprising since we examined the impact of referral, rather than attendance or completion of the intervention.

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

AIMS: The NHS Diabetes Prevention Programme (NHS DPP) is a large-scale, England-wide behaviour change programme for people at high risk of progressing to type 2 diabetes. We summarise the findings of our six-year DIPLOMA evaluation of its implementation and impact and highlight insights for future programmes. METHODS: Using qualitative interviews, document analysis, observation, surveys and large dataset analysis, eight interlinked work packages considered: equity of access; implementation; service delivery and fidelity; programme outcomes; comparative effectiveness and cost-effectiveness in reducing diabetes incidence; and patient decision making and experience. RESULTS: Delivery of the NHS DPP encountered barriers across many aspects of the programme, and we identified inequalities in terms of the areas, organisations and patient populations most likely to engage with the programme. There was some loss of fidelity at all stages from commissioning to participant understanding. Despite these challenges, there was evidence of significant reductions in diabetes incidence at individual and population levels. The programme was cost-effective even within a short time period. CONCLUSIONS: Despite the challenge of translating research evidence into routine NHS delivery at scale, our findings suggest that an individual-level approach to the prevention of type 2 diabetes in a 'high-risk' population was more effective than usual care. By embedding evaluation with programme delivery and working closely with the NHS DPP team, we provided actionable insights for improving communications with potential participants, supporting primary care referral, honing the delivery model with better provider relationships and more patient choice, increasing understanding of behaviour change techniques, and enriching the educational and health coaching content.

A qualitative evaluation of the national rollout of a diabetes prevention programme in England.

BACKGROUND: The National Health Service Diabetes Prevention Programme (NHS DPP) was commissioned by NHS England in 2016 and rolled out in three 'waves' across the whole of England. It aims to help people with raised blood glucose levels reduce their risk of developing type 2 diabetes through behaviour change techniques (e.g., weight loss, dietary changes and exercise). An independent, longitudinal, mixed methods evaluation of the NHS DPP was undertaken. We report the findings from the implementation work package: a qualitative interview study with designated local leads, responsible for the local commissioning and implementation of the programme. The aim of the study was to explore how local implementation processes were enacted and adapted over time. METHODS: We conducted a telephone interview study across two time-points. Twenty-four semi-structured interviews with local leads across 19 sampled case sites were undertaken between October 2019 and January 2020 and 13 interviews with local leads across 13 sampled case sites were conducted between July 2020 and August 2020. Interviews aimed to reflect on the experience of implementation and explore how things changed over time. RESULTS: We identified four overarching themes to show how implementation was locally enacted and adapted across the sampled case sites: 1. Adapting to provider change; 2. Identification and referral; 3. Enhancing uptake in underserved populations; and 4. Digital and remote service options. CONCLUSION: This paper reports how designated local leads, responsible for local implementation of the NHS DPP, adapted implementation efforts over the course of a changing national diabetes prevention programme, including how local leads adapted implementation during the COVID-19 pandemic. This paper highlights three main factors that influence implementation: the importance of facilitation, the ability (or not) to tailor interventions to local needs and the role of context in implementation.

'Finishing the race' - a cohort study of weight and blood glucose change among the first 36,000 patients in a large-scale diabetes prevention programme.

BACKGROUND: The NHS Diabetes Prevention Programme for England, "Healthier You", encourages behaviour change regarding healthy eating and physical exercise among people identified to be at high risk of developing type 2 diabetes. The aim of this research was to examine change, and factors associated with change, in measures of HbA1c and weight in participants and completers of the programme between 2016 and 2019. METHODS: Participant-level data collected by programme service providers on referrals prior to March 2018 was analysed. Changes from baseline to both 6 months and completion in HbA1c and weight were examined using mixed effects linear regression, adjusting for patient characteristics, service provider and site. RESULTS: Completers had average improvements in HbA1c of 2.1 mmol/mol [95% CI: - 2.2, - 2.0] (0.19% [95% CI: - 0.20, - 0.18]) and reductions of 3.6 kg [95% CI: - 3.6, - 3.5] in weight, in absolute terms. Variation across the four providers was observed at both time points: two providers had significantly smaller average reductions in HbA1c and one provider had a significantly smaller average reduction in weight compared to the other providers. At both time points, ex- or current smokers had smaller reductions in HbA1c than non-smokers and those from minority ethnic groups lost less weight than White participants. For both outcomes, associations with other factors were small or null and variation across sites remained after adjustment for provider and case mix. CONCLUSIONS: Participants who completed the programme, on average, experienced improvements in weight and HbA1c. There was substantial variation in HbA1c change and smaller variation in weight loss between providers and across different sites. Aside from an association between HbA1c change and smoking, and between weight loss and ethnicity, results were broadly similar regardless of patient characteristics.

Could diabetes prevention programmes result in the widening of sociodemographic inequalities in type 2 diabetes? Comparison of survey and administrative data for England.

BACKGROUND: The NHS Diabetes Prevention Programme (DPP) in England is a behavioural intervention for preventing type 2 diabetes mellitus (T2DM) among people with non-diabetic hyperglycaemia (NDH). How this programme affects inequalities by age, sex, limiting illnesses or disability, ethnicity or deprivation is not known. METHODS: We used multinomial and binary logistic regression models to compare whether the population with NDH at different stages of the programme are representative of the population with NDH: stages include (1) prevalence of NDH (using survey data from UK Household Longitudinal Study (n=794) and Health Survey for England (n=1383)); (2) identification in primary care and offer of programme (using administrative data from the National Diabetes Audit (n=1 267 350)) and (3) programme participation (using programme provider records (n=98 024)). RESULTS: Predicted probabilities drawn from the regressions with demographics as each outcome and dataset identifier as predictors showed that younger adults (aged under 40) (4% of the population with NDH (95% CI 2.4% to 6.5%)) and older adults (aged 80 and above) (12% (95% CI 9.5% to 14.2%)) were slightly under-represented among programme participants (2% (95% CI 1.8% to 2.2%) and 8% (95% CI 7.8% to 8.2%) of programme participants, respectively). People living in deprived areas were under-represented in eight sessions (14% (95% CI 13.7% to 14.4%) vs 20% (95% CI 16.4% to 23.6%) in the general population). Ethnic minorities were over-represented among offers (35% (95% CI 35.1% to 35.6%) vs 13% (95% CI 9.1% to 16.4%) in general population), though the proportion dropped at the programme completion stage (19% (95% CI 18.5% to 19.5%)). CONCLUSION: The DPP has the potential to reduce ethnic inequalities, but may widen socioeconomic, age and limiting illness or disability-related inequalities in T2DM. While ethnic minority groups are over-represented at the identification and offer stages, efforts are required to support completion of the programme. Programme providers should target under-represented groups to ensure equitable access and narrow inequalities in T2DM.

Reflections of patient and public involvement from a commissioned research project evaluating a nationally implemented NHS programme focused on diabetes prevention.

Patient and Public Involvement and Engagement (PPIE) in research is recognised by the National Institute for Health and Care Research as crucial for high quality research with practical benefit for patients and carers. Patient and public contributors can provide both personal knowledge and lived experiences which complement the perspectives of the academic research team. Nevertheless, effective PPIE must be tailored to the nature of the research, such as the size and scope of the research, whether it is researcher-led or independently commissioned, and whether the research aims to design an intervention or evaluate it. For example, commissioned research evaluations have potential limits on how PPIE can feed into the design of the research and the intervention. Such constraints may require re-orientation of PPIE input to other functions, such as supporting wider engagement and dissemination. In this commentary, we use the 'Guidance for Reporting Involvement of Patients and the Public' (GRIPP2) short form to share our own experiences of facilitating PPIE for a large, commissioned research project evaluating the National Health Service Diabetes Prevention Programme; a behavioural intervention for adults in England who are at high risk of developing type 2 diabetes. The programme was already widely implemented in routine practice when the research project and PPIE group were established. This commentary provides us with a unique opportunity to reflect on experiences of being part of a PPIE group in the context of a longer-term evaluation of a national programme, where the scope for involvement in the intervention design was more constrained, compared to PPIE within researcher-led intervention programmes. We reflect on PPIE in the design, analysis and dissemination of the research, including lessons learned for future PPIE work in large-scale commissioned evaluations of national programmes. Important considerations for this type of PPIE work include: ensuring the role of public contributors is clarified from the outset, the complexities of facilitating PPIE over longer project timeframes, and providing adequate support to public contributors and facilitators (including training, resources and flexible timelines) to ensure an inclusive and considerate approach. These findings can inform future PPIE plans for stakeholders involved in commissioned research.

'Going the distance': an independent cohort study of engagement and dropout among the first 100 000 referrals into a large-scale diabetes prevention program.

INTRODUCTION: Diabetes prevention programs (DPPs) are effective, in a pre-diabetic population, in reducing weight, lowering glycated hemoglobin and slowing the progression to diabetes. Little is known about the relationship between participation in DPPsand participant characteristics or service delivery. We investigated uptake and retention in England's NHS DPP, reporting on variability among patient subgroups, providers, and sites. RESEARCH DESIGN AND METHODS: This prospective cohort study included 99 473 adults with non-diabetic hyperglycemia referred to the English DPP between 2016 and 2017. The program seeks to change health behaviors by offering at least 16 hours of group education and exercise. Multilevel logistic regression models were used to analyze variation in uptake, retention, and completion. RESULTS: Uptake among 99 473 adults referred to the program was 56% (55 275). Among 55 275 who started the program, 34% (18 562) achieved the required dose and 22% (12 127) completed the full course. After adjustment for variation in case mix, substantial heterogeneity in uptake and retention was seen across four service providers (uptake OR 1.77 (1.33, 2.34), 4.30 (3.01, 6.15), and 1.45 (1.07, 1.97) compared with the reference provider) and between sites (uptake for typical individuals ranged from 0.32 to 0.78 across the middle 95% of sites, intraclass correlation coefficient (ICC) 0.07). Higher levels of retention and completion were seen where some out-of-hours provision was offered (retention OR 1.32 (1.25, 1.39)). CONCLUSIONS: This study provides the first independent assessment of participation in the English DPP and the first study internationally to examine the impact of DPP service delivery on participation. When implementing a large-scale DPP, heterogeneity in service provision between different providers and sites can result in variable participation beyond that attributable to case mix, with potential consequences for effectiveness and health inequalities. Extending out-of-hours provision may improve participation in prevention programs.

Epidemiology and determinants of non-diabetic hyperglycaemia and its conversion to type 2 diabetes mellitus, 2000-2015: cohort population study using UK electronic health records.

OBJECTIVES: To study the characteristics of UK individuals identified with non-diabetic hyperglycaemia (NDH) and their conversion rates to type 2 diabetes mellitus (T2DM) from 2000 to 2015, using the Clinical Practice Research Datalink. DESIGN: Cohort study. SETTINGS: UK primary Care Practices. PARTICIPANTS: Electronic health records identified 14 272 participants with NDH, from 2000 to 2015. PRIMARY AND SECONDARY OUTCOME MEASURES: Baseline characteristics and conversion trends from NDH to T2DM were explored. Cox proportional hazards models evaluated predictors of conversion. RESULTS: Crude conversion was 4% within 6 months of NDH diagnosis, 7% annually, 13% within 2 years, 17% within 3 years and 23% within 5 years. However, 1-year conversion fell from 8% in 2000 to 4% in 2014. Individuals aged 45-54 were at the highest risk of developing T2DM (HR 1.20, 95% CI 1.15 to 1.25- compared with those aged 18-44), and the risk reduced with older age. A body mass index (BMI) above 30 kg/m2 was strongly associated with conversion (HR 2.02, 95% CI 1.92 to 2.13-compared with those with a normal BMI). Depression (HR 1.10, 95% CI 1.07 to 1.13), smoking (HR 1.07, 95% CI 1.03 to 1.11-compared with non-smokers) or residing in the most deprived areas (HR 1.17, 95% CI 1.11 to 1.24-compared with residents of the most affluent areas) was modestly associated with conversion. CONCLUSION: Although the rate of conversion from NDH to T2DM fell between 2010 and 2015, this is likely due to changes over time in the cut-off points for defining NDH, and more people of lower diabetes risk being diagnosed with NDH over time. People aged 45-54, smokers, depressed, with high BMI and more deprived are at increased risk of conversion to T2DM.

Verbal protocols for assessing the usability of clinical decision support: the retrospective sense making protocol.

We compare the effectiveness of two types of verbal protocol, concurrent think aloud vs. retrospective sense making, for evaluating the usability of a clinical decision support tool. Thirty-five medical and nursing students participated in a usability experiment. Participants were asked to complete seven tasks using the system under evaluation. Eighteen students were allocated to the concurrent think aloud group and the remainder followed the retrospective protocol. The retrospective protocol was significantly more sensitive than the concurrent protocol in recording unique usability problems related to users' cognitive behaviour. These problems concerned the interpretation and comprehension of statistical output, search results and system messages. These findings can be explained by the retrospective protocol's greater ability to detect compound usability problems, capturing the cognitive dimensions of users' interactions with the interface in greater depth. Evaluations of clinical decision support systems should take an evidence-based approach to selecting protocols.

e-Labs and the stock of health method for simulating health policies.

Regional outcomes of national health policies are difficult to forecast. This is partly due to a lack of realistically complex models that can be used to appraise policy options and partly a lack of accessible and adaptable tools that can be used to simulate the consequences of policy decisions. These barriers might be overcome by exploiting the commoditization of massively parallel computing architectures, advances in machine learning, and the increased availability of large-scale linked healthcare data. This paper presents a novel modelling methodology, The Stock of Health, for harnessing emerging data and computational resources to simulate health policy, with application initially to coronary heart disease. We detail the use of multi-core graphical processing architectures to facilitate a micro-simulation approach. The simulation tools have been deployed through the IMPACT Framework. We explore how this framework can be extended to support the sharing and reuse of policy models and simulations based on the digital publishing concept of e-Lab.