Level of attendance at the English National Health Service Diabetes Prevention Programme and risk of progression to type 2 diabetes.

BACKGROUND: We evaluated the dose-response relationship between the level of attendance at the English National Health Service Diabetes Prevention Programme (DPP) and risk of progression to type 2 diabetes amongst individuals participating in the programme. METHODS: We linked data on DPP attendance for 51,803 individuals that were referred to the programme between 1st June 2016 and 31st March 2018 and attended at least one programme session, with primary care records of type 2 diabetes diagnoses from the National Diabetes Audit up to 31st March 2020. Weibull survival regressions were used to estimate the association between the number of programme sessions attended and risk of progression to type 2 diabetes. RESULTS: Risk of developing type 2 diabetes declined significantly for individuals attending seven of the 13 programme sessions and continued to decline further up to 12 sessions. Attending the full 13 sessions was associated with a 45.5% lower risk (HR: 0.545 95% CI: 0.455 to 0.652). Compared to individuals that only partially attended the programme, attendance at 60% or more of the sessions was associated with a 30.7% lower risk of type 2 diabetes (HR: 0.693 95% CI: 0.645 to 0.745). CONCLUSIONS: Reducing the risk of progression to type 2 diabetes through diabetes prevention programmes requires a minimum attendance level at seven of the 13 programme sessions (54%). Retaining participants beyond this minimum level yields further benefits in diabetes risk reduction. Commissioners may wish to consider altering provider payment schedules to incentivise higher retention levels beyond 60% of programme sessions.

Age- and deprivation-related inequalities in identification of people at high risk of type 2 diabetes in England.

BACKGROUND: Early detection of intermediate hyperglycaemia, otherwise known as non-diabetic hyperglycaemia (NDH) is crucial to identify people at high risk of developing type 2 diabetes mellitus (T2DM) who could benefit from preventative interventions. Failure to identify NDH may also increase the risks of T2DM-related complications at the time of T2DM diagnosis. We investigate sociodemographic inequalities in identification of NDH in England. METHODS: We used nationwide data from the English National Health Service (NHS) National Diabetes Audit, which includes all people who were newly identified with NDH (N = 469,910) or diagnosed with T2DM (N = 222,795) between 1st April 2019 and 31st March 2020. We used regression models to explore inequalities in the under identification of NDH by area-level deprivation and age group. RESULTS: Of those with a new T2DM diagnosis, 67.3% had no previous record of NDH. The odds of no previous NDH being recorded were higher amongst people living in more deprived areas (Odds ratio (OR) 1.15 (95% confidence intervals (CI) [1.12, 1.19]) most deprived (Q1) compared to least deprived (Q5) quintile) and younger individuals (OR 4.02 (95% CI [3.79, 4.27] under 35s compared to age 75-84)). Deprivation-related inequalities persisted after stratification by age group, with the largest inequalities amongst middle and older age groups. People living in more deprived areas and younger people also had shorter recorded NDH duration before progression to T2DM, and higher T2DM severity at the time of diagnosis. CONCLUSIONS: There is under identification of NDH relative to diagnosis of T2DM amongst people living in more deprived areas and particularly amongst younger people, resulting in missed opportunities for targeted T2DM prevention efforts and potentially contributing to inequalities in T2DM prevalence and severity. More active NDH case-finding amongst these groups may be an important first step in helping to reduce inequalities in T2DM.

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.

The effects of structure, process and outcome incentives on primary care referrals to a national prevention programme.

Despite widespread use, evidence is sparse on whether financial incentives in healthcare should be linked to structure, process or outcome. We examine the impact of different incentive types on the quantity and effectiveness of referrals made by general practices to a new national prevention programme in England. We measured effectiveness by the number of referrals resulting in programme attendance. We surveyed local commissioners about their use of financial incentives and linked this information to numbers of programme referrals and attendances from 5170 general practices between April 2016 and March 2018. We used multivariate probit regressions to identify commissioner characteristics associated with the use of different incentive types and negative binomial regressions to estimate their effect on practice rates of referral and attendance. Financial incentives were offered by commissioners in the majority of areas (89%), with 38% using structure incentives, 69% using process incentives and 22% using outcome incentives. Compared to practices without financial incentives, neither structure nor process incentives were associated with statistically significant increases in referrals or attendances, but outcome incentives were associated with 84% more referrals and 93% more attendances. Outcome incentives were the only form of pay-for-performance to stimulate more participation in this national disease prevention programme.

Barriers and Facilitators to Model Replication Within Health Economics.

BACKGROUND: Model replication is important because it enables researchers to check research integrity and transparency and, potentially, to inform the model conceptualization process when developing a new or updated model. OBJECTIVE: The aim of this study was to evaluate the replicability of published decision analytic models and to identify the barriers and facilitators to replication. METHODS: Replication attempts of 5 published economic modeling studies were made. The replications were conducted using only publicly available information within the manuscripts and supplementary materials. The replicator attempted to reproduce the key results detailed in the paper, for example, the total cost, total outcomes, and if applicable, incremental cost-effectiveness ratio reported. Although a replication attempt was not explicitly defined as a success or failure, the replicated results were compared for percentage difference to the original results. RESULTS: In conducting the replication attempts, common barriers and facilitators emerged. For most case studies, the replicator needed to make additional assumptions when recreating the model. This was often exacerbated by conflicting information being presented in the text and the tables. Across the case studies, the variation between original and replicated results ranged from -4.54% to 108.00% for costs and -3.81% to 0.40% for outcomes. CONCLUSION: This study demonstrates that although models may appear to be comprehensively reported, it is often not enough to facilitate a precise replication. Further work is needed to understand how to improve model transparency and in turn increase the chances of replication, thus ensuring future usability.

Evaluating the Long-Term Cost-Effectiveness of the English NHS Diabetes Prevention Programme using a Markov Model.

BACKGROUND: In 2016, England launched the largest nationwide diabetes mellitus prevention programme, the NHS Diabetes Prevention Programme (NHS DPP). This paper seeks to evaluate the long-term cost-effectiveness of this programme. METHODS: A Markov cohort state transition model was developed with a 35-year time horizon and yearly cycles to compare referral to the NHS DPP to usual care for individuals with non-diabetic hyperglycaemia. The modelled cohort of individuals mirrored the age profile of referrals received by the programme by April 2020. A health system perspective was taken, with costs in UK £ Sterling (price year 2020) and outcomes in terms of quality-adjusted life-years (QALYs). Probabilistic analysis with 10,000 Monte Carlo simulations was used. Several sensitivity analyses were conducted to explore the uncertainty surrounding the base case results, particularly varying the length of time for which the effectiveness of the programme was expected to last. RESULTS: In the base case, using only the observed effectiveness of the NHS DPP at 3 years, it was found that the programme is likely to dominate usual care, by generating on average 40.8 incremental QALYs whilst saving £135,755 in costs for a cohort of 1000. At a willingness to pay of £20,000 per QALY, 98.1% of simulations were on or under the willingness-to-pay threshold. Scaling this up to the number of referrals actually received by the NHS DPP prior to April 2020, cost savings of £71.4 million were estimated over the 35-year time horizon and an additional 21,472 QALYs generated. These results are robust to several sensitivity analyses. CONCLUSION: The NHS DPP is likely to be cost-effective. Indeed, in the majority of the simulations, the NHS DPP was cost-saving and generated greater QALYs, dominating usual care. This research should serve as evidence to support the continued investment or recommissioning of diabetes prevention programmes.

Cardiac rehabilitation for children and young people (CardioActive): protocol for a single-blind randomised feasibility and acceptability study of a centre-based cardiac rehabilitation programme versus usual care in 11-16 years with heart conditions.

BACKGROUND: Congenital heart conditions are among the most common non-communicable diseases in children and young people (CYP), affecting 13.9 million CYP globally. While survival rates are increasing, support for young people adjusting to life with a heart condition is lacking. Furthermore, one in three CYP with heart conditions also experiences anxiety, depression or adjustment disorder, for which little support is offered. While adults are offered cardiac rehabilitation (CR) to support their mental and physical health, this is not offered for CYP.One way to overcome this is to evaluate a CR programme comprising exercise with mental health support (CardioActive; CA) for CYP with heart conditions. The exercise and mental health components are informed by the metacognitive model, which has been shown to be effective in treating anxiety and depression in CYP and associated with improving psychological outcomes in adult CR. METHOD AND ANALYSIS: The study is a single-blind parallel randomised feasibility trial comparing a CR programme (CA) plus usual care against usual care alone with 100 CYP (50 per arm) aged 11-16 diagnosed with a heart condition. CA will include six group exercise, lifestyle and mental health modules. Usual care consists of routine outpatient management. Participants will be assessed at three time points: baseline, 3-month (post-treatment) and 6-month follow-up. Primary outcomes are feasibility and acceptability (ie, referral rates, recruitment and retention rates, attendance at the intervention, rate of return and level of completion of follow-up data). Coprimary symptom outcomes (Strength and Difficulties Questionnaire and Paediatric Quality of Life) and a range of secondary outcomes will be administered at each time point. A nested qualitative study will investigate CYP, parents and healthcare staff views of CR and its components, and staff's experience of delivering CA. Preliminary health economic data will be collected to inform future cost-effectiveness analyses. Descriptive data on study processes and clinical outcomes will be reported. Data analysis will follow intention to treat. Qualitative data will be analysed using thematic analysis and the theoretical framework of acceptability. ETHICS AND DISSEMINATION: Ethical approval was granted on 14 February 2023 by the Greater Manchester East Research Ethics Committee (22/NW/0367). The results will be disseminated through peer-reviewed journals, conference presentations and local dissemination. TRIAL REGISTRATION NUMBER: ISRCTN50031147; NCT05968521.

Evaluating the Short-Term Costs and Benefits of a Nationwide Diabetes Prevention Programme in England: Retrospective Observational Study.

BACKGROUND: Prevention programmes typically incur short-term costs and uncertain long-term benefits. We use the National Health Service (NHS) England Diabetes Prevention Programme (NHS-DPP) to investigate whether behaviour change programmes may be cost-effective even within the short-term participation period. METHODS: We analysed 384,611 referrals between June 2016 and March 2019. We estimated NHS costs using implementation costs and provider payments. We used linear regressions to relate utility changes to the number of sessions attended, based on responses to the five-level EQ-5D (EQ-5D-5L) at baseline and final session for 18,959 participants. We then calculated the corresponding quality-adjusted life year (QALY) change for all 384,611 referrals by combining the estimated regression coefficients with the observed level of attendance, with individuals that did not attend any programme sessions being assumed to experience zero benefit. In secondary analysis, we added weight change, recorded for 18,105 participants to the regression and applied predicted values to all referrals with missing weight change values estimated using multiple imputation with chained equations. We then estimated the cost-per-QALY generated. RESULTS: Average cost per referral was £119 (standard deviation: £118; 2020 price year, UK £ Sterling). Each session attended was associated with a 0.0042 increase in utility (95% confidence interval (CI): 0.0025-0.0059). This generated 1,773 QALYs across all referrals (95% CI: 889-2,656). Cost-per-QALY was £24,929 (95% CI: £16,635-49,720) when implementation costs were excluded. Secondary analysis showed each session attended and kilogram of weight lost were associated with 0.0034 (95% CI: 0.0016-0.0051) and 0.0025 (95% CI: 0.0020-0.0031) increases in utility, respectively. These generated 1,542 QALYs, at a cost-per-QALY of £28,661 when implementation costs were excluded. CONCLUSION: Participants experienced small utility gains from session attendance and weight loss during their programme participation. These benefits alone made this low-cost behaviour change programme potentially cost-effective in the short-term.

Does recruiting patients to diabetes prevention programmes via primary care reinforce existing inequalities in care provision between general practices? A retrospective observational study.

BACKGROUND: Primary care plays a crucial role in identifying patients' needs and referring at-risk individuals to preventive services. However, well-established variations in care delivery may be replicated in this prevention activity. OBJECTIVE: To examine whether recruiting patients to the English NHS Diabetes Prevention Programme via primary care reinforces existing inequalities in care provision between practices, in terms of clinical quality, accessibility and resources. METHODS: We generated annual practice-level counts of referrals across the first 4 years of the programme (June 2016 to March 2020). These were linked to 15 indicators of practice clinical quality, access and resources measured during 2018/19. We used random effects Poisson regressions to examine associations between referrals and these indicators, controlling for practice and population characteristics, for 6871 practices in England. RESULTS: On average, practices made 3.72 referrals per 1000 population annually and rates varied substantially between practices. Referral rates were positively associated with the quality of clinical care provided. A 1 SD higher level of achievement on Quality and Outcomes Framework diabetes indicators was associated with an 11% (95% CI: 8% to 14%) higher referral rate. This positive association was consistent across all five clinical quality indicators. There was no association between referral rates and accessibility, overall payments or staffing. Associations between referrals and receiving different supplementary payments over the core contract were mixed, with 8%-11% lower referral rates for some payments but not for others. CONCLUSION: Recruiting patients to diabetes prevention programmes via primary care reinforces existing inequalities between general practices in the clinical quality of care they provide. This leaves patients registered with practices providing lower quality clinical care even more disadvantaged. Providing additional support to lower quality practices or using alternative recruitment methods may be necessary to avoid differential engagement in prevention programmes from widening these variations and potential health inequalities further.