Sociodemographic disparities in non-diabetic hyperglycaemia and the transition to type 2 diabetes: evidence from the English Longitudinal Study of Ageing

The effectiveness and cost-effectiveness of the NHS Diabetes Prevention Programme (NHS-DPP): the DIPLOMA long-term multimethod assessment

Background

Type 2 diabetes is considered a critical challenge to modern healthcare systems. The National Health Service Diabetes Prevention Programme delivered an evidence-based behaviour change programme at a national scale to reduce the incidence of type 2 diabetes in England.

Objective(s)

The Diabetes Prevention - Long-term Multimethod Assessment research programme provided a comprehensive assessment of the delivery of the National Health Service Diabetes Prevention Programme and its effectiveness and cost-effectiveness.

Design

Mixed-methods research including qualitative methods, observations, patient surveys and secondary analysis of administrative and survey data using statistical and econometric methods.

Setting

Community settings in England delivering the commissioned intervention, supported by general practices responsible for recruitment and referral.

Participants

Patients in community settings identified as being at high risk of type 2 diabetes offered and participating in the National Health Service Diabetes Prevention Programme, and staff involved in the organisation and delivery of the service.

Interventions

The National Health Service Diabetes Prevention Programme, including its evidence-based behaviour change intervention (using both face-to-face and digital platforms) and the associated services for patient recruitment.

Main outcome measures

Incidence of type 2 diabetes, cost-effectiveness, access to the programme and fidelity of intervention delivery.

Data sources

Interviews with patients and staff, document analysis and observations of the National Health Service Diabetes Prevention Programme delivery, patient surveys, secondary data (including National Health Service Diabetes Prevention Programme data, national surveys and audits).

Results

The National Health Service Diabetes Prevention Programme was associated with significant reductions in incidence of type 2 diabetes and was highly likely to be cost-effective. Analyses of the delivery of the programme highlighted several aspects which impacted access to the programme and the fidelity with which the behaviour change intervention was delivered. For example, uptake and adherence were influenced by participants' psychosocial beliefs (e.g. chance of getting type 2 diabetes and whether taking part would reduce this). There were large differences between general practices in how many people they referred to the programme, with practices that offered higher-quality care for people with diabetes referring more. Variation in retention and outcomes was associated with differences in providers.

Limitations

Analysis of administrative data to explore effectiveness and cost-effectiveness may be influenced by confounding. Recruitment of diverse and representative samples for surveys, interviews and observations was likely impacted by selection.

Conclusions

The National Health Service Diabetes Prevention Programme is highly likely to be cost-effective. Data from Diabetes Prevention - Long-term Multimethod Assessment have been used to improve aspects of programme delivery and could suggest further enhancements to improve recruitment, retention and fidelity.

Future work

Future research should address the question of whether the National Health Service Diabetes Prevention Programme prevents or delays type 2 diabetes when longer-term follow-up data are available. We identified factors that could be targeted to impact on recruitment, retention and inequalities, and recommend a robust assessment of the link between fidelity and outcomes.

Funding

This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme as award number 16/48/07.

Risk factors for progression to type 2 diabetes in prediabetes: a systematic review and meta-analysis

BACKGROUND

Prediabetes is the earliest identifiable stage of glycemic dysregulation, and its progression can be delayed by effective control of risk factors. Currently, various risk factors for the progression from prediabetes to type 2 diabetes mellitus (T2DM) need to be further summarized.

OBJECTIVE

This systematic evaluation of the risk factors for the progression of prediabetes to type 2 diabetes mellitus provides a theoretical basis for early recognition and intervention. The meta-analysis identifies the Fatty Liver Index as a significant risk factor [OR = 6.14, 95% CI (5.22, 7.22)] for the progression from prediabetes to type 2 diabetes, highlighting its predictive value.

METHODS

PubMed, Web of Science, Embase, The Cochrane Library, CNKI, WANFANG, and VIP databases were searched to collect cohort studies on risk factors for progressing to type 2 diabetes in prediabetes from inception to February 15, 2024. STATA 17.0 was used for Meta-analysis.

RESULTS

A total of 59 studies were included, all of which were of medium to high quality. The factors were categorized into four major groups: sociodemographic factors, lifestyle factors, psychosocial factors, and comorbidities and clinical indicators. Meta-analysis results showed that sociodemographic factors [age [OR = 1.03, 95% CI (1.01, 1.04)], family history [OR = 1.48, 95% CI (1.36, 1.61)], male sex [OR = 1.13, 95% CI (1.08, 1.19)], high BMI [OR = 1.21, 95% CI (1.15, 1.27)], high waist circumference [OR = 1.49, 95% CI (1.23, 1.79)], and high waist-to-hip ratio [OR = 2.44, 95% CI (2.17, 2.74)]]. Lifestyle factors included a lack of physical exercise [OR = 1.86, 95% CI (1.19, 2.88)], smoking [OR = 1.31, 95% CI (1.22, 1.41)], and moderate physical activity [OR = 0.24, 95% CI (0.09, 0.67)]. Psychosocial factors included anxiety [OR = 2.61, 95% CI (1.36, 5.00)], depression [OR = 1.88, 95% CI (1.35, 2.61)], and social deprivation level 4 [OR = 1.15, 95% CI (1.13, 1.18)]. Comorbidities and clinical indicators included hypertension [OR = 1.41, 95% CI (1.33, 1.50)], high triglycerides [OR = 1.25, 95% CI (1.10, 1.43)], high cholesterol [OR = 1.09, 95% CI (1.06, 1.12)], fatty liver index [OR = 6.14, 95% CI (5.22, 7.22)], low HDL-C [OR = 1.13, 95% CI (1.09, 1.36)], and high blood glucose levels [OR = 1.01, 95% CI (1.01, 1.02)].

CONCLUSIONS

This study found that age, male sex, positive family history of type 2 diabetes, high BMI, unhealthy lifestyle, anxiety, depression, high blood pressure, high triglycerides, and a high fatty liver index are risk factors for the progression from prediabetes to type 2 diabetes and should be given sufficient attention. Moderate physical activity and Low HDL-C are protective factors. Future studies should also increase follow-up, explore the best diagnostic criteria for prediabetes, and fully consider the definitions of various factors. The study was registered in PROSPERO (CRD42024513931).

From inequalities to solutions: an explanatory sequential study on type 2 diabetes health services utilization

BACKGROUND

Health inequities are a significant issue. This study aimed to measure and decompose socioeconomic inequality in the utilization of type 2 diabetes (T2D) services and propose solutions to mitigate these inequalities.

METHODS

This explanatory sequential mixed-method study was conducted in two phases: quantitative and qualitative. A total of 2000 T2D patients from health centers, hospitals, and diabetes clinics in Isfahan and Khuzestan provinces, Iran, were selected. In the quantitative phase, the existence of inequality in the utilization of T2D services was examined using the Concentration Index (CI) approach. To determine the contribution of each explanatory variable to T2D inequality, we used concentration index decomposition analysis. In the qualitative phase, based on the main contributors identified in the quantitative phase, we conducted semi-structured interviews with purposefully selected key experts to identify solutions for reducing inequality in the utilization of T2D services.

RESULTS

The sample consisted of 65.3% men, with 40% of T2D patients being over 60 years old. The CI values were 0.31 (p < 0.05) for outpatient services, -0.10 (p > 0.05) for inpatient services, and 0.11 (p < 0.05) for pharmaceutical services. This indicates an inequality in the utilization of outpatient and pharmaceutical services among T2D patients, while the inequality in inpatient services was not significant. The main variables contributing to inequality in outpatient services were health status (33.54%), basic insurance (27.43%), and socioeconomic status (24.08%). For pharmaceutical services, the contributing variables were health status (22.20%), basic insurance (13.63%), and socioeconomic status (34.35%). Experts' solutions to reduce socioeconomic inequalities in Iran were classified into three main themes: socioeconomic status, health status, and basic insurance, with 29 sub-themes.

CONCLUSION

The results suggest that targeted health interventions for poor T2D patients are recommended. Efforts towards universal coverage in outpatient care and commonly used pharmaceutical items, such as: Antidiabetic Drugs, Triglyceride Control Drugs, Cardiovascular Drugs, Neuropathy Drugs, and Nephropathy Drugs, should be considered.

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.

A Scoping Review of Possible Solutions for Decreasing Socioeconomic Inequalities in Type 2 Diabetes Mellitus

Background

As socioeconomic inequalities are key factors in access and utilization of type 2 diabetes (T2D) services, the purpose of this scoping review was to identify solutions for decreasing socioeconomic inequalities in T2D.

Methods

A scoping review of scientific articles from 2000 and later was conducted using PubMed, Web of Science (WOS), Scopus, Embase, and ProQuest databases. Using the Arksey and O'Malley framework for scoping review, articles were extracted, meticulously read, and thematically analyzed.

Results

A total of 7204 articles were identified from the reviewed databases. After removing duplicate and nonrelevant articles, 117 articles were finally included and analyzed. A number of solutions and passways were extracted from the final articles. Solutions for decreasing socioeconomic inequalities in T2D were categorized into 12 main solutions and 63 passways.

Conclusions

Applying identified solutions in diabetes policies and interventions would be recommended for decreasing socioeconomic inequalities in T2D. Also, the passways could be addressed as entry points to help better implementation of diabetic policies.

The effectiveness of digital delivery versus group-based face-to-face delivery of the English National Health Service Type 2 Diabetes Prevention Programme: a non-inferiority retrospective cohort comparison study

BACKGROUND

Face-to-face group-based diabetes prevention programmes have been shown to be effective in many settings. Digital delivery may suit some patients, but research comparing the effectiveness of digital with face-to-face delivery is scarce. The aim was to assess if digital delivery of the English National Health Service Diabetes Prevention Programme (NHS DPP) is non-inferior to group-based face-to-face delivery in terms of weight change, and evaluate factors associated with differential change.

METHODS

The study included those recruited to the NHS DPP in 2017-2018. Individual-level data from a face-to-face cohort was compared to two cohorts on a digital pilot who (i) were offered no choice of delivery mode, or (ii) chose digital over face-to-face. Changes in weight at 6 and 12 months were analysed using mixed effects linear regression, having matched participants from the digital pilot to similar participants from face-to-face.

RESULTS

Weight change on the digital pilot was non-inferior to face-to-face at both time points: it was similar in the comparison of those with no choice (difference in weight change: -0.284 kg [95% CI: -0.712, 0.144] at 6 months) and greater in digital when participants were offered a choice (-1.165 kg [95% CI: -1.841, -0.489]). Interactions between delivery mode and sex, ethnicity, age and deprivation were observed.

CONCLUSIONS

Digital delivery of the NHS DPP achieved weight loss at least as good as face-to-face. Patients who were offered a choice and opted for digital experienced better weight loss, compared to patients offered face-to-face only.

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.

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.

The influence of demographic, health and psychosocial factors on patient uptake of the English NHS diabetes prevention programme

BACKGROUND

The prevention of type 2 diabetes (T2DM) is a major concern for health services around the world. The English NHS Diabetes Prevention Programme (NHS-DPP) offers a group face-to-face behaviour change intervention, based around exercise and diet, to adults with non-diabetic hyperglycaemia (NDH), referred from primary care. Previous analysis of the first 100,000 referrals revealed just over half of those referred to the NHS-DPP took up a place. This study aimed to identify the demographic, health and psychosocial factors associated with NHS-DPP uptake to help inform the development of interventions to improve uptake and address inequities between population groups.

METHODS

Drawing on the Behavioral Model of Health Services Utilization we developed a survey questionnaire to collect data on a wide range of demographic, health and psychosocial factors that might influence uptake of the NHS-DPP. We distributed this questionnaire to a cross-sectional random sample of 597 patients referred to the NHS-DPP across 17 general practices, chosen for variation. Multivariable regression analysis was used to identify factors associated with NHS-DPP uptake.

RESULTS

325 out of 597 questionnaires were completed (54%). Only a third of responders took up the offer of a place. The best performing model for uptake (AUC = 0.78) consisted of four factors: older age; beliefs concerning personal vulnerability to T2DM; self-efficacy for reducing T2DM risk; and the efficacy of the NHS-DPP. After accounting for these, demographic and health-related factors played only a minor role.

CONCLUSION

Unlike fixed demographic characteristics, psychosocial perceptions may be amenable to change. NHS-DPP uptake rates may be improved by targeting the beliefs of patients about their risk of developing T2DM, their ability to carry out and sustain behaviours to reduce this risk, and the efficacy of the NHS-DPP in providing the necessary understanding and skills required. The recently introduced digital version of the NHS DPP could help address the even lower uptake amongst younger adults. Such changes could facilitate proportional access from across different demographic strata.

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.

It is time for a more targeted approach to prediabetes in primary care in Aotearoa New Zealand

Type 2 diabetes (T2DM), its related morbidities and entrenched diabetes-related inequities pose significant challenges for health care delivery systems in Aotearoa New Zealand (NZ). Primary care services undertake the majority of diabetes prevention work by initially detecting and managing those with prediabetes. In this viewpoint, we present available NZ data to highlight NZ trends in prediabetes and consider the current NZ clinical guidelines and the prediabetes care pathway. Multiple areas for improvement are identified to optimise diabetes prevention, potentially reduce T2DM inequities, and sustain more effective prediabetes management in primary care in NZ.

Population level impact of the NHS Diabetes Prevention Programme on incidence of type 2 diabetes in England: An observational study

BACKGROUND

The NHS Diabetes Prevention Programme (DPP) is the first nationwide type 2 diabetes prevention programme targeting people with prediabetes. It was rolled out across England from 2016 in three waves. We evaluate the population level impact of the NHS DPP on incidence rates of type 2 diabetes.

METHODS

We use data from the National Diabetes Audit, which records all individuals across England who have been diagnosed with type 2 diabetes by 2019. We use difference-in-differences regression models to estimate the impact of the phased introduction of the DPP on type 2 diabetes incidence. We compare patients registered with the 3,282 general practices enrolled from 2016 (wave 1) and the 1,610 practices enrolled from 2017 (wave 2) to those registered with the 1,584 practices enrolled from 2018 (final wave).

FINDINGS

Incidence rates of type 2 diabetes in wave 1 practices in 2018 and 2019 were significantly lower than would have been expected in the absence of the DPP (difference-in-differences Incident Rate Ratio (IRR) = 0·938 (95% CI 0·905 to 0·972)). Incidence rates were also significantly lower than expected for wave 2 practices in 2019 (difference-in-differences IRR = 0·927 (95% CI 0·885 to 0·972)). These results remained consistent across several robustness checks.

INTERPRETATION

Introduction of the NHS DPP reduced population incidence of type 2 diabetes. Longer follow-up is required to explore whether these effects are maintained or if diabetes onset is delayed.

FUNDING

This research was funded by the National Institute for Health and Care Research (Health Services and Delivery Research, 16/48/07 - Evaluating the NHS Diabetes Prevention Programme (NHS DPP): the DIPLOMA research programme (Diabetes Prevention - Long Term Multimethod Assessment)). The views and opinions expressed in this manuscript are those of the authors and do not necessarily reflect those of the NHS, the National Institute for Health and Care Research or the Department of Health and Social Care.

Variation in appropriate diabetes care and treatment targets in urban and rural areas in England: an observational study of the 'rule of halves'

OBJECTIVES

To estimate the 'rule of halves' for diabetes care for urban and rural areas in England using several data sources covering the period 2015-2017; and to examine the extent to which any differences in urban and rural settings are explained by population characteristics and the workforce supply of primary care providers (general practices).

DESIGN

A retrospective observational study.

SETTING

Populations resident in predominantly urban and rural areas in England (2015-2017).

PARTICIPANTS

N=33 336 respondents to the UK Household Longitudinal Survey in urban and rural settings in England; N=4913 general practices in England reporting to the National Diabetes Audit and providing workforce data to NHS Digital.

OUTCOMES

Diabetes prevalence; administrative records of diagnoses of diabetes; provision of (all eight) recommended diabetes care processes; diabetes treatment targets.

RESULTS

Diabetes prevalence was higher in urban areas in England (7.80% (95% CI 7.30% to 8.31%)) relative to rural areas (7.24% (95% CI 6.32% to 8.16%)). For practices in urban areas, relatively fewer cases of diabetes were recorded in administrative medical records (69.55% vs 71.86%), and a smaller percentage of those registered received the appropriate care (45.85% vs 49.32%). Among estimated prevalent cases of diabetes, urban areas have a 24.84% achieving these targets compared with 25.16% in rural areas. However, adjusted analyses showed that the performance of practices in urban areas in providing appropriate care quality was not significantly different from practices in rural areas.

CONCLUSIONS

The 'rule of halves' is not an accurate description of the actual pattern across the diabetes care pathway in England. More than half of the estimated urban and rural diabetes population are registered with clinical practices and have access to treatment. However, less than half of those registered for treatment have achieved treatment targets. Appropriate care quality was associated with a greater proportion of patients with diabetes achieving treatment targets.