The impact of Type 2 diabetes prevention programmes based on risk-identification and lifestyle intervention intensity strategies: a cost-effectiveness analysis

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.

Cost-effectiveness analysis of two interventions to promote physical activity in a multiethnic population at high risk of diabetes: an economic evaluation of the 48-month PROPELS randomized controlled trial

INTRODUCTION

Physical activity (PA) is protective against type 2 diabetes (T2D). However, data on pragmatic long-term interventions to reduce the risk of developing T2D via increased PA are lacking. This study investigated the cost-effectiveness of a pragmatic PA intervention in a multiethnic population at high risk of T2D.

MATERIALS AND METHODS

We adapted the School for Public Health Research diabetes prevention model, using the PROPELS trial data and analyses of the NAVIGATOR trial. Lifetime costs, lifetime quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated for each intervention (Walking Away (WA) and Walking Away Plus (WA+)) versus usual care and compared with National Institute for Health and Care Excellence's willingness-to-pay of £20 000-£30 000 per QALY gained. We conducted scenario analyses on the outcomes of the PROPELS trial data and a threshold analysis to determine the change in step count that would be needed for the interventions to be cost-effective.

RESULTS

Estimated lifetime costs for usual care, WA, and WA+ were £22 598, £23 018, and £22 945, respectively. Estimated QALYs were 9.323, 9.312, and 9.330, respectively. WA+ was estimated to be more effective and cheaper than WA. WA+ had an ICER of £49 273 per QALY gained versus usual care. In none of our scenario analyses did either WA or WA+ have an ICER below £20 000 per QALY gained. Our threshold analysis suggested that a PA intervention costing the same as WA+ would have an ICER below £20 000/QALY if it were to achieve an increase in step count of 500 steps per day which was 100% maintained at 4 years.

CONCLUSIONS

We found that neither WA nor WA+ was cost-effective at a limit of £20 000 per QALY gained. Our threshold analysis showed that interventions to increase step count can be cost-effective at this limit if they achieve greater long-term maintenance of effect.

TRIAL REGISTRATION NUMBER

ISRCTN registration: ISRCTN83465245: The PRomotion Of Physical activity through structuredEducation with differing Levels of ongoing Support for those with pre-diabetes (PROPELS)https://doi.org/10.1186/ISRCTN83465245.

Incorporating frailty to address the key challenges to geriatric economic evaluation

BACKGROUND

The multidimensional and dynamically complex process of ageing presents key challenges to economic evaluation of geriatric interventions, including: (1) accounting for indirect, long-term effects of a geriatric shock such as a fall; (2) incorporating a wide range of societal, non-health outcomes such as informal caregiver burden; and (3) accounting for heterogeneity within the demographic group. Measures of frailty aim to capture the multidimensional and syndromic nature of geriatric health. Using a case study of community-based falls prevention, this article explores how incorporating a multivariate frailty index in a decision model can help address the above key challenges.

METHODS

A conceptual structure of the relationship between geriatric shocks and frailty was developed. This included three key associations involving frailty: (A) the shock-frailty feedback loop; (B) the secondary effects of shock via frailty; and (C) association between frailty and intervention access. A case study of economic modelling of community-based falls prevention for older persons aged 60 + was used to show how parameterising these associations contributed to addressing the above three challenges. The English Longitudinal Study of Ageing (ELSA) was the main data source for parameterisation. A new 52-item multivariate frailty index was generated from ELSA. The main statistical methods were multivariate logistic and linear regressions. Estimated regression coefficients were inputted into a discrete individual simulation with annual cycles to calculate the continuous variable value or probability of binary event given individuals' characteristics.

RESULTS

All three conceptual associations, in their parameterised forms, contributed to addressing challenge (1). Specifically, by worsening the frailty progression, falls incidence in the model increased the risk of falling in subsequent cycles and indirectly impacted the trajectories and levels of EQ-5D-3 L, mortality risk, and comorbidity care costs. Intervention access was positively associated with frailty such that the greater access to falls prevention by frailer individuals dampened the falls-frailty feedback loop. Association (B) concerning the secondary effects of falls via frailty was central to addressing challenge (2). Using this association, the model was able to estimate how falls prevention generated via its impact on frailty paid and unpaid productivity gains, out-of-pocket care expenditure reduction, and informal caregiving cost reduction. For challenge (3), frailty captured the variations within demographic groups of key model outcomes including EQ-5D-3 L, QALY, and all-cause care costs. Frailty itself was shown to have a social gradient such that it mediated socially inequitable distributions of frailty-associated outcomes.

CONCLUSION

The frailty-based conceptual structure and parameterisation methods significantly improved upon the methods previously employed by falls prevention models to address the key challenges for geriatric economic evaluation. The conceptual structure is applicable to other geriatric and non-geriatric intervention areas and should inform the data selection and statistical methods to parameterise structurally valid economic models of geriatric interventions.

Evaluation of a workplace weight management program based on WeChat platform for obese/overweight people in China using the RE-AIM framework

A Weight Management Program (WMP) is a critical and promising approach to losing excess weight and maintaining a healthy lifestyle for obese/overweight people. This study used the RE-AIM framework to retrospectively evaluate a WeChat-based workplace WMP that include low- and high-intensity interventions - self-management (SM) and intensive support (IS) - designed for employees with varying levels of health risk at a Chinese company. Both interventions incorporated with a variety of m-health technologies and behavioral strategies. While the IS group additionally received personalized feedback on diet record and intensive social support. Approximately 26% of all overweight/obese employees in the company enrolled in the program. Both groups lost a significant amount of weight at the endpoint (P < 0.001). In comparison to the SM group, the IS group had significantly higher level of compliance with self-monitoring. At six-month, 67% of individuals reported no additional weight gain. The WeChat-based WMP has received widespread praise from program participants and intervention providers in spite of difficulties encountered. This comprehensive and meticulous evaluation revealed both the strengths and weaknesses of the program, which will assist in improving implementation and balancing the cost and effectiveness of online WMP.

Preventing type 2 diabetes: A research agenda for behavioural science

AIMS

The aim of this narrative review was to identify important knowledge gaps in behavioural science relating to type 2 diabetes prevention, to inform future research in the field.

METHODS

Seven researchers who have published behaviour science research applied to type 2 diabetes prevention independently identified several important gaps in knowledge. They met to discuss these and to generate recommendations to advance research in behavioural science of type 2 diabetes prevention.

RESULTS

A total of 21 overlapping recommendations for a research agenda were identified. These covered issues within the following broad categories: (a) evidencing the impact of whole population approaches to type 2 diabetes prevention, (b) understanding the utility of disease-specific approaches to type 2 diabetes prevention such as Diabetes Prevention Programmes (DPPs) compared to generic weight loss programmes, (c) identifying how best to increase reach and engagement of DPPs, whilst avoiding exacerbating inequalities, (d) the need to understand mechanism of DPPs, (e) the need to understand how to increase maintenance of changes as part of or following DPPs, (f) the need to assess the feasibility and effectiveness of alternative approaches to the typical self-regulation approaches that are most commonly used, and (g) the need to address emotional aspects of DPPs, to promote effectiveness and avoid harms.

CONCLUSIONS

There is a clear role for behavioural science in informing interventions to prevent people from developing type 2 diabetes, based on strong evidence of reach, effectiveness and cost-effectiveness. This review identifies key priorities for research needed to improve existing interventions.

Prediction of complications in health economic models of type 2 diabetes: a review of methods used

AIM

Diabetes health economic (HE) models play important roles in decision making. For most HE models of diabetes 2 diabetes (T2D), the core model concerns the prediction of complications. However, reviews of HE models pay little attention to the incorporation of prediction models. The objective of the current review is to investigate how prediction models have been incorporated into HE models of T2D and to identify challenges and possible solutions.

METHODS

PubMed, Web of Science, Embase, and Cochrane were searched from January 1, 1997, to November 15, 2022, to identify published HE models for T2D. All models that participated in The Mount Hood Diabetes Simulation Modeling Database or previous challenges were manually searched. Data extraction was performed by two independent authors. Characteristics of HE models, their underlying prediction models, and methods of incorporating prediction models were investigated.

RESULTS

The scoping review identified 34 HE models, including a continuous-time object-oriented model (n = 1), discrete-time state transition models (n = 18), and discrete-time discrete event simulation models (n = 15). Published prediction models were often applied to simulate complication risks, such as the UKPDS (n = 20), Framingham (n = 7), BRAVO (n = 2), NDR (n = 2), and RECODe (n = 2). Four methods were identified to combine interdependent prediction models for different complications, including random order evaluation (n = 12), simultaneous evaluation (n = 4), the 'sunflower method' (n = 3), and pre-defined order (n = 1). The remaining studies did not consider interdependency or reported unclearly.

CONCLUSIONS

The methodology of integrating prediction models in HE models requires further attention, especially regarding how prediction models are selected, adjusted, and ordered.

A non-invasive risk score including skin autofluorescence predicts diabetes risk in the general population

Increased skin autofluorescence (SAF) predicts the development of diabetes-related complications and cardiovascular disease. We assessed the performance of a simple model which includes SAF to identify individuals at high risk for undiagnosed and incident type 2 diabetes, in 58,377 participants in the Lifelines Cohort Study without known diabetes. Newly-diagnosed diabetes was defined as fasting blood glucose ≥ 7.0 mmol/l and/or HbA_1c ≥ 6.5% (≥ 48 mmol/mol) or self-reported diabetes at follow-up. We constructed predictive models based on age, body mass index (BMI), SAF, and parental history of diabetes, and compared to results with the concise FINDRISC model. At 2nd visit to Lifelines, 1113 (1.9%) participants were identified with undiagnosed diabetes and 1033 (1.8%) participants developed diabetes during follow-up. A model comprising age, BMI and SAF yielded an AUC of 0.783 and was non-inferior to the concise FINDRISC model, which had an AUC of 0.797 to predict new diabetes. At a score of 5.8, sensitivity was 78% and specificity of 66%. Model 2 which also incorporated parental diabetes history, had an AUC of 0.792, and a sensitivity of 74% and specificity of 70% at a score of 6.5. Net reclassification index (NRI) did not improve significantly (NRI 1.43% (- 0.50-3.37 p = 0.15). The combination of an easy to perform SAF measurement with age and BMI is a good alternative screening tool suitable for medical and non-medical settings. Parental history of diabetes did not significantly improve model performance in this homogeneous cohort.

BMI trajectories, morbidity, and mortality in England: a two-step approach to estimating consequences of changes in BMI

OBJECTIVE

BMI is known to have an association with morbidities and mortality. Many studies have argued that identifying health risks using single BMI measures has limitations, particularly in older adults, and that changes in BMI can help to identify risks. This study identifies distinct BMI trajectories and their association with the risks of a range of morbidities and mortality.

METHODS

The English Longitudinal Study of Aging provides data on BMI, mortality, and morbidities between 1998 and 2015, sampled from adults over 50 years of age. This study uses a growth-mixture model and discrete-time survival analysis, combined using a two-step approach, which is novel in this setting, to the authors' knowledge.

RESULTS

This study identified four trajectories: "stable overweight," "elevated BMI," "increasing BMI," and "decreasing BMI." No differences in mortality, cancer, or stroke risk were found between these trajectories. BMI trajectories were significantly associated with the risks of diabetes, asthma, arthritis, and heart problems.

CONCLUSIONS

These results emphasize the importance of looking at change in BMI alongside most recent BMI; BMI trajectories should be considered where possible when assessing health risks. The results suggest that established BMI thresholds should not be used in isolation to identify health risks, particularly in older adults.

The health, cost and equity impacts of restrictions on the advertisement of high fat, salt and sugar products across the transport for London network: a health economic modelling study

BACKGROUND

Policies aimed at restricting the marketing of high fat, salt and sugar products have been proposed as one way of improving population diet and reducing obesity. In 2019, Transport for London implemented advertising restrictions on high fat, salt and sugar products. A controlled interrupted time-series analysis comparing London with a north of England control, suggested that the advertising restrictions had resulted in a reduction in household energy purchases. The aim of the study presented here was to estimate the health benefits, cost savings and equity impacts of the Transport for London policy using a health economic modelling approach, from an English National Health Service and personal social services perspective.

METHODS

A diabetes prevention microsimulation model was modified to incorporate the London population and Transport for London advertising intervention. Conversion of calorie to body mass index reduction was mediated through an approximation of a mathematical model estimating weight loss. Outcomes gathered included incremental obesity, long-term diabetes and cardiovascular disease events, quality-adjusted life years, healthcare costs saved and net monetary benefit. Slope index of inequality was calculated for proportion of people with obesity across socioeconomic groups to assess equity impacts.

RESULTS

The results show that the Transport for London policy was estimated to have resulted in 94,867 (4.8%) fewer individuals with obesity, and to reduce incidence of diabetes and cardiovascular disease by 2,857 and 1,915 cases respectively within three years post intervention. The policy would produce an estimated 16,394 additional quality-adjusted life-years and save £218 m in NHS and social care costs over the lifetime of the current population. Greater benefits (e.g. a 37% higher gain in quality-adjusted life-years) were expected to accrue to individuals from the most socioeconomically deprived groups compared to the least deprived.

CONCLUSIONS

This analysis suggests that there are considerable potential health and economic gains from restricting the advertisement of high fat, salt and sugar products. The population health and economic impacts of the Transport for London advertising restrictions are likely to have reduced health inequalities in London.

Systematic review and critical methodological appraisal of community-based falls prevention economic models

BACKGROUND

Falls impose significant health and economic burdens on community-dwelling older persons. Decision modelling can inform commissioning of alternative falls prevention strategies. Several methodological challenges arise when modelling public health interventions including community-based falls prevention. This study aims to conduct a systematic review (SR) to: systematically identify community-based falls prevention economic models; synthesise and critically appraise how the models handled key methodological challenges associated with public health modelling; and suggest areas for further methodological research.

METHODS

The SR followed the 2021 PRISMA reporting guideline and covered the period 2003-2020 and 12 academic databases and grey literature. The extracted methodological features of included models were synthesised by their relevance to the following challenges: (1) capturing non-health outcomes and societal intervention costs; (2) considering heterogeneity and dynamic complexity; (3) considering theories of human behaviour and implementation; and (4) considering equity issues. The critical appraisal assessed the prevalence of each feature across models, then appraised the methods used to incorporate the feature. The methodological strengths and limitations stated by the modellers were used as indicators of desirable modelling practice and scope for improvement, respectively. The methods were also compared against those suggested in the broader empirical and methodological literature. Areas of further methodological research were suggested based on appraisal results.

RESULTS

46 models were identified. Comprehensive incorporation of non-health outcomes and societal intervention costs was infrequent. The assessments of heterogeneity and dynamic complexity were limited; subgroup delineation was confined primarily to demographics and binary disease/physical status. Few models incorporated heterogeneity in intervention implementation level, efficacy and cost. Few dynamic variables other than age and falls history were incorporated to characterise the trajectories of falls risk and general health/frailty. Intervention sustainability was frequently based on assumptions; few models estimated the economic/health returns from improved implementation. Seven models incorporated ethnicity- and severity-based subgroups but did not estimate the equity-efficiency trade-offs. Sixteen methodological research suggestions were made.

CONCLUSION

Existing community-based falls prevention models contain methodological limitations spanning four challenge areas relevant for public health modelling. There is scope for further methodological research to inform the development of falls prevention and other public health models.

Using health economic modelling to inform the design and development of an intervention: estimating the justifiable cost of weight loss maintenance in the UK

BACKGROUND

There is a need to develop cost-effective weight loss maintenance interventions to prolong the positive impact of weight loss on health outcomes. Conducting pre-trial health economic modelling is recommended to inform the design and development of behavioural interventions. We aimed to use health economic modelling to estimate the maximum cost per-person (justifiable cost) of a cost-effective behavioural weight loss maintenance intervention, given an estimated intervention effect for individuals with: i) a Body Mass Index (BMI) of 28 kg/m2 or above without diabetes and ii) a diagnosis of type 2 diabetes prescribed a single non-insulin diabetes medication.

METHODS

The School for Public Health Research Diabetes prevention model was used to estimate the lifetime Quality-adjusted life year (QALY) gains, healthcare costs, and maximum justifiable cost associated with a weight loss maintenance intervention. Based on a meta-analysis, the estimated effect of a weight loss maintenance intervention following a 9 kg weight loss, was a regain of 1.33 kg and 4.38 kg in years one and two respectively compared to greater regain of 2.84 kg and 5.6 kg in the control group. Sensitivity analysis was conducted around the rate of regain, duration of effect and initial weight loss.

RESULTS

The justifiable cost for a weight loss maintenance intervention at an ICER of £20,000 per QALY was £104.64 for an individual with a BMI of 28 or over and £88.14 for an individual with type 2 diabetes. Within sensitivity analysis, this varied from £36.42 to £203.77 for the former, and between £29.98 and £173.05 for the latter.

CONCLUSIONS

Researchers developing a weight loss maintenance intervention should consider these maximum justifiable cost estimates and the potential impact of the duration of effect and initial weight loss when designing intervention content and deciding target populations. Future research should consider using the methods demonstrated in this study to use health economic modelling to inform the design and budgetary decisions in the development of a behavioural interventions.

Behavioural interventions to promote physical activity in a multiethnic population at high risk of diabetes: PROPELS three-arm RCT

BACKGROUND

Type 2 diabetes is a leading cause of mortality globally and accounts for significant health resource expenditure. Increased physical activity can reduce the risk of diabetes. However, the longer-term clinical effectiveness and cost-effectiveness of physical activity interventions in those at high risk of type 2 diabetes is unknown.

OBJECTIVES

To investigate whether or not Walking Away from Diabetes (Walking Away) - a low-resource, 3-hour group-based behavioural intervention designed to promote physical activity through pedometer use in those with prediabetes - leads to sustained increases in physical activity when delivered with and without an integrated mobile health intervention compared with control.

DESIGN

Three-arm, parallel-group, pragmatic, superiority randomised controlled trial with follow-up conducted at 12 and 48 months.

SETTING

Primary care and the community.

PARTICIPANTS

Adults whose primary care record included a prediabetic blood glucose measurement recorded within the past 5 years [HbA_1c ≥ 42 mmol/mol (6.0%), < 48 mmol/mol (6.5%) mmol/mol; fasting glucose ≥ 5.5 mmol/l, < 7.0 mmol/l; or 2-hour post-challenge glucose ≥ 7.8 mmol/l, < 11.1 mmol/l] were recruited between December 2013 and February 2015. Data collection was completed in July 2019.

INTERVENTIONS

Participants were randomised (1 : 1 : 1) using a web-based tool to (1) control (information leaflet), (2) Walking Away with annual group-based support or (3) Walking Away Plus (comprising Walking Away, annual group-based support and a mobile health intervention that provided automated, individually tailored text messages to prompt pedometer use and goal-setting and provide feedback, in addition to biannual telephone calls). Participants and data collectors were not blinded; however, the staff who processed the accelerometer data were blinded to allocation.

MAIN OUTCOME MEASURES

The primary outcome was accelerometer-measured ambulatory activity (steps per day) at 48 months. Other objective and self-reported measures of physical activity were also assessed.

RESULTS

A total of 1366 individuals were randomised (median age 61 years, median body mass index 28.4 kg/m², median ambulatory activity 6638 steps per day, women 49%, black and minority ethnicity 28%). Accelerometer data were available for 1017 (74%) and 993 (73%) individuals at 12 and 48 months, respectively. The primary outcome assessment at 48 months found no differences in ambulatory activity compared with control in either group (Walking Away Plus: 121 steps per day, 97.5% confidence interval -290 to 532 steps per day; Walking Away: 91 steps per day, 97.5% confidence interval -282 to 463). This was consistent across ethnic groups. At the intermediate 12-month assessment, the Walking Away Plus group had increased their ambulatory activity by 547 (97.5% confidence interval 211 to 882) steps per day compared with control and were 1.61 (97.5% confidence interval 1.05 to 2.45) times more likely to achieve 150 minutes per week of objectively assessed unbouted moderate to vigorous physical activity. In the Walking Away group, there were no differences compared with control at 12 months. Secondary anthropometric, biomechanical and mental health outcomes were unaltered in either intervention study arm compared with control at 12 or 48 months, with the exception of small, but sustained, reductions in body weight in the Walking Away study arm (≈ 1 kg) at the 12- and 48-month follow-ups. Lifetime cost-effectiveness modelling suggested that usual care had the highest probability of being cost-effective at a threshold of £20,000 per quality-adjusted life-year. Of 50 serious adverse events, only one (myocardial infarction) was deemed possibly related to the intervention and led to the withdrawal of the participant from the study.

LIMITATIONS

Loss to follow-up, although the results were unaltered when missing data were replaced using multiple imputation.

CONCLUSIONS

Combining a physical activity intervention with text messaging and telephone support resulted in modest, but clinically meaningful, changes in physical activity at 12 months, but the changes were not sustained at 48 months.

FUTURE WORK

Future research is needed to investigate which intervention types, components and features can help to maintain physical activity behaviour change over the longer term.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN83465245.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 77. See the NIHR Journals Library website for further project information.

Psychological interventions to improve self-management of type 1 and type 2 diabetes: a systematic review

BACKGROUND

For people with diabetes mellitus to achieve optimal glycaemic control, motivation to perform self-management is important. The research team wanted to determine whether or not psychological interventions are clinically effective and cost-effective in increasing self-management and improving glycaemic control.

OBJECTIVES

The first objective was to determine the clinical effectiveness of psychological interventions for people with type 1 diabetes mellitus and people with type 2 diabetes mellitus so that they have improved (1) glycated haemoglobin levels, (2) diabetes self-management and (3) quality of life, and fewer depressive symptoms. The second objective was to determine the cost-effectiveness of psychological interventions.

DATA SOURCES

The following databases were accessed (searches took place between 2003 and 2016): MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, PsycINFO, EMBASE, Cochrane Controlled Trials Register, Web of Science, and Dissertation Abstracts International. Diabetes conference abstracts, reference lists of included studies and Clinicaltrials.gov trial registry were also searched.

REVIEW METHODS

Systematic review, aggregate meta-analysis, network meta-analysis, individual patient data meta-analysis and cost-effectiveness modelling were all used. Risk of bias of randomised and non-randomised controlled trials was assessed using the Cochrane Handbook (Higgins JP, Altman DG, Gøtzsche PC, Jüni P, Moher D, Oxman AD, et al. The Cochrane Collaboration's tool for assessing risk of bias in randomised trials. BMJ 2011;343:d5928).

DESIGN

Systematic review, meta-analysis, cost-effectiveness analysis and patient and public consultation were all used.

SETTING

Settings in primary or secondary care were included.

PARTICIPANTS

Adolescents and children with type 1 diabetes mellitus and adults with types 1 and 2 diabetes mellitus were included.

INTERVENTIONS

The interventions used were psychological treatments, including and not restricted to cognitive-behavioural therapy, counselling, family therapy and psychotherapy.

MAIN OUTCOME MEASURES

Glycated haemoglobin levels, self-management behaviours, body mass index, blood pressure levels, depressive symptoms and quality of life were all used as outcome measures.

RESULTS

A total of 96 studies were included in the systematic review (n = 18,659 participants). In random-effects meta-analysis, data on glycated haemoglobin levels were available for seven studies conducted in adults with type 1 diabetes mellitus (n = 851 participants) that demonstrated a pooled mean difference of -0.13 (95% confidence interval -0.33 to 0.07), a non-significant decrease in favour of psychological treatment; 18 studies conducted in adolescents/children with type 1 diabetes mellitus (n = 2583 participants) that demonstrated a pooled mean difference of 0.00 (95% confidence interval -0.18 to 0.18), indicating no change; and 49 studies conducted in adults with type 2 diabetes mellitus (n = 12,009 participants) that demonstrated a pooled mean difference of -0.21 (95% confidence interval -0.31 to -0.10), equivalent to reduction in glycated haemoglobin levels of -0.33% or ≈3.5 mmol/mol. For type 2 diabetes mellitus, there was evidence that psychological interventions improved dietary behaviour and quality of life but not blood pressure, body mass index or depressive symptoms. The results of the network meta-analysis, which considers direct and indirect effects of multiple treatment comparisons, suggest that, for adults with type 1 diabetes mellitus (7 studies; 968 participants), attention control and cognitive-behavioural therapy are clinically effective and cognitive-behavioural therapy is cost-effective. For adults with type 2 diabetes mellitus (49 studies; 12,409 participants), cognitive-behavioural therapy and counselling are effective and cognitive-behavioural therapy is potentially cost-effective. The results of the individual patient data meta-analysis for adolescents/children with type 1 diabetes mellitus (9 studies; 1392 participants) suggest that there were main effects for age and diabetes duration. For adults with type 2 diabetes mellitus (19 studies; 3639 participants), baseline glycated haemoglobin levels moderated treatment outcome.

LIMITATIONS

Aggregate meta-analysis was limited to glycaemic control for type 1 diabetes mellitus. It was not possible to model cost-effectiveness for adolescents/children with type 1 diabetes mellitus and modelling for type 2 diabetes mellitus involved substantial uncertainty. The individual patient data meta-analysis included only 40-50% of studies.

CONCLUSIONS

This review suggests that psychological treatments offer minimal clinical benefit in improving glycated haemoglobin levels for adults with type 2 diabetes mellitus. However, there was no evidence of benefit compared with control interventions in improving glycated haemoglobin levels for people with type 1 diabetes mellitus.

FUTURE WORK

Future work should consider the competency of the interventionists delivering a therapy and psychological approaches that are matched to a person and their life course.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016033619.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 28. See the NIHR Journals Library website for further project information.

Targeting of the diabetes prevention program leads to substantial benefits when capacity is constrained

OBJECTIVE

Approximately 84 million people in the USA have pre-diabetes, but only a fraction of them receive proven effective therapies to prevent type 2 diabetes. We estimated the value of prioritizing individuals at highest risk of progression to diabetes for treatment, compared to non-targeted treatment of individuals meeting inclusion criteria for the Diabetes Prevention Program (DPP).

METHODS

Using microsimulation to project outcomes in the DPP trial population, we compared two interventions to usual care: (1) lifestyle modification and (2) metformin administration. For each intervention, we compared targeted and non-targeted strategies, assuming either limited or unlimited program capacity. We modeled the individualized risk of developing diabetes and projected diabetic outcomes to yield lifetime costs and quality-adjusted life expectancy, from which we estimated net monetary benefits (NMB) for both lifestyle and metformin versus usual care.

RESULTS

Compared to usual care, lifestyle modification conferred positive benefits and reduced lifetime costs for all eligible individuals. Metformin's NMB was negative for the lowest population risk quintile. By avoiding use when costs outweighed benefits, targeted administration of metformin conferred a benefit of $500 per person. If only 20% of the population could receive treatment, when prioritizing individuals based on diabetes risk, rather than treating a 20% random sample, the difference in NMB ranged from $14,000 to $20,000 per person.

CONCLUSIONS

Targeting active diabetes prevention to patients at highest risk could improve health outcomes and reduce costs compared to providing the same intervention to a similar number of patients with pre-diabetes without targeted selection.

The Impact of Including Costs and Outcomes of Dementia in a Health Economic Model to Evaluate Lifestyle Interventions to Prevent Diabetes and Cardiovascular Disease

Objectives

Economic evaluations of lifestyle interventions, which aim to prevent diabetes/cardiovascular disease (CVD), have not included dementia. Lifestyle interventions decrease dementia risk and extend life expectancy, leading to competing effects on health care costs. We aim to demonstrate the feasibility of including dementia in a public health cost-effectiveness analysis and quantify the overall impacts accounting for these competing effects.

Methods

The School for Public Health Research (SPHR) diabetes prevention model describes individuals’ risk of type 2 diabetes, microvascular outcomes, CVD, congestive heart failure, cancer, osteoarthritis, depression, and mortality in England. In version 3.1, we adapted the model to include dementia using published data from primary care databases, health surveys, and trials of dementia to describe dementia incidence, diagnosis, and disease progression. We estimate the impact of dementia on lifetime costs and quality-adjusted life years (QALYs) gained of the National Health Service diabetes prevention program (NHS DPP) from an NHS/personal social services perspective with 3 scenarios: 1) no dementia, 2) dementia only, and 3) reduced dementia risk. Subgroup, parameter, and probabilistic sensitivity analyses were conducted.

Results

The lifetime cost savings of the NHS DPP per patient were £145 in the no-dementia scenario, £121 in the dementia-only scenario, and £167 in the reduced dementia risk scenario. The QALY gains increased by 0.0006 in dementia only and 0.0134 in reduced dementia risk. Dementia did not alter the recommendation that the NHS/DPP is cost-effective.

Conclusions

Including dementia into a model of lifestyle interventions was feasible but did not change policy recommendations or modify health economic outcomes. The impact on health economic outcomes was largest where a direct impact on dementia incidence was assumed, particularly in elderly populations.

What are the cost-savings and health benefits of improving detection and management for six high cardiovascular risk conditions in England? An economic evaluation

OBJECTIVES

To estimate the cost savings and health benefits of improving detection of individuals at high risk of cardiovascular disease (CVD) in England, to determine to which patient subgroups these benefits arise, and to compare different strategies for subsequent management.

DESIGN

An economic analysis using the School for Public Health Research CVD Prevention Model.

SETTING

England 2018.

PARTICIPANTS

Adults aged 16 and older with one or more high cardiovascular risk conditions, including hypertension, diabetes, non-diabetic hyperglycaemia, atrial fibrillation, chronic kidney disease and high cholesterol.

INTERVENTIONS

Detection of 100% of individuals with CVD high risk conditions compared with current levels of detection in England. Detected individuals are assumed to be managed either according to current levels of care or National Institute of Health and Care Excellence (NICE) guidelines.

MAIN OUTCOME MEASURES

Incremental and cumulative costs, savings, quality adjusted life years (QALYs), CVD cases, and net monetary benefit, from a UK NHS and Personal Social Services perspective.

RESULTS

£68 billion could be saved, 4.9 million QALYs gained and 3.4 million cases of CVD prevented over 25 years if all individuals in England with the six CVD high risk conditions were diagnosed and subsequently managed at current levels. Additionally, if all detected individuals were managed according to NICE guidelines, total savings would be £61 billion, 8.1 million QALYs would be gained and 5.2 million CVD cases prevented. Most benefits come from detection of high cholesterol in the short term and diabetes in the long term.

CONCLUSIONS

Substantial cost savings and health benefits would accrue if all individuals with conditions that increase CVD risk could be diagnosed, with detection of undiagnosed diabetes producing greatest benefits. Ensuring all conditions are managed according to NICE guidelines would further increase health benefits. Projected cost-savings could be invested in developing acceptable and cost-effective solutions for improving detection and management.

Cost-effectiveness of Diabetes Prevention Interventions Targeting High-risk Individuals and Whole Populations: A Systematic Review

OBJECTIVE

We conducted a systematic review of studies evaluating the cost-effectiveness (CE) of interventions to prevent type 2 diabetes (T2D) among high-risk individuals and whole populations.

RESEARCH DESIGN AND METHODS

Interventions targeting high-risk individuals are those that identify people at high risk of developing T2D and then treat them with either lifestyle or metformin interventions. Population-based prevention strategies are those that focus on the whole population regardless of the level of risk, creating public health impact through policy implementation, campaigns, and other environmental strategies. We systematically searched seven electronic databases for studies published in English between 2008 and 2017. We grouped lifestyle interventions targeting high-risk individuals by delivery method and personnel type. We used the median incremental cost-effectiveness ratio (ICER), measured in cost per quality-adjusted life year (QALY) or cost saved to measure the CE of interventions. We used the $50,000/QALY threshold to determine whether an intervention was cost-effective or not. ICERs are reported in 2017 U.S. dollars.

RESULTS

Our review included 39 studies: 28 on interventions targeting high-risk individuals and 11 targeting whole populations. Both lifestyle and metformin interventions in high-risk individuals were cost-effective from a health care system or a societal perspective, with median ICERs of $12,510/QALY and $17,089/QALY, respectively, compared with no intervention. Among lifestyle interventions, those that followed a Diabetes Prevention Program (DPP) curriculum had a median ICER of $6,212/QALY, while those that did not follow a DPP curriculum had a median ICER of $13,228/QALY. Compared with lifestyle interventions delivered one-on-one or by a health professional, those offered in a group setting or provided by a combination of health professionals and lay health workers had lower ICERs. Among population-based interventions, taxing sugar-sweetened beverages was cost-saving from both the health care system and governmental perspectives. Evaluations of other population-based interventions-including fruit and vegetable subsidies, community-based education programs, and modifications to the built environment-showed inconsistent results.

CONCLUSIONS

Most of the T2D prevention interventions included in our review were found to be either cost-effective or cost-saving. Our findings may help decision makers set priorities and allocate resources for T2D prevention in real-world settings.

Decision models of prediabetes populations: A systematic review

AIMS

With evidence supporting the use of preventive interventions for prediabetes populations and the use of novel biomarkers to stratify the risk of progression, there is a need to evaluate their cost-effectiveness across jurisdictions. Our aim is to summarize and assess the quality and validity of decision models and model-based economic evaluations of populations with prediabetes, to evaluate their potential use for the assessment of novel prevention strategies and to discuss the knowledge gaps, challenges and opportunities.

MATERIALS AND METHODS

We searched Medline, Embase, EconLit and NHS EED between 2000 and 2018 for studies reporting computer simulation models of the natural history of individuals with prediabetes and/or we used decision models to evaluate the impact of treatment strategies on these populations. Data were extracted following PRISMA guidelines and assessed using modelling checklists. Two reviewers independently assessed 50% of the titles and abstracts to determine whether a full text review was needed. Of these, 10% was assessed by each reviewer to cross-reference the decision to proceed to full review. Using a standardized form and double extraction, each of four reviewers extracted 50% of the identified studies.

RESULTS

A total of 29 published decision models that simulate prediabetes populations were identified. Studies showed large variations in the definition of prediabetes and model structure. The inclusion of complications in prediabetes (n = 8) and type 2 diabetes (n = 17) health states also varied. A minority of studies simulated annual changes in risk factors (glycaemia, HbA1c, blood pressure, BMI, lipids) as individuals progressed in the models (n = 7) and accounted for heterogeneity among individuals with prediabetes (n = 7).

CONCLUSIONS

Current prediabetes decision models have considerable limitations in terms of their quality and validity and do not allow evaluation of stratified strategies using novel biomarkers, highlighting a clear need for more comprehensive prediabetes decision models.

Dexamethasone implant for non-infectious uveitis: is it cost-effective?

BACKGROUND

Uveitis is inflammation inside the eye. The objective of this study is to assess the cost-effectiveness of a dexamethasone implant plus current practice (immunosuppressants and systemic corticosteroids) compared with current practice alone, in patients with non-infectious intermediate, posterior or pan-uveitis and to identify areas for future research.

METHODS

A Markov model was built to estimate the costs and benefits of dexamethasone. Systematic reviews were performed to identify available relevant evidence. Quality of life data from the key randomised-controlled trial (HURON) was used to estimate the interventions' effectiveness compared with the trial's comparator arm (placebo plus limited current practice (LCP)). The analysis took a National Health Service and Personal Social Services perspective. Costs were calculated based on standard UK sources.

RESULTS

The incremental cost-effectiveness ratio (ICER) of one dexamethasone implant compared with LCP is estimated as £19 509 per quality-adjusted life year (QALY) gained. The factors with the largest impact on the results were rate of blindness and relative proportion of blindness cases avoided by dexamethasone. Using plausible alternative assumptions, dexamethasone could be cost saving or it may be associated with an ICER of £56 329 per QALY gained compared with LCP.

CONCLUSIONS

Dexamethasone is estimated to be cost-effective using generally accepted UK thresholds. However, there is substantial uncertainty around these results due to scarcity of evidence. Future research on the following would help provide more reliable estimates: effectiveness of dexamethasone versus current practice (instead of LCP), with subgroup analyses for unilateral and bilateral uveitis, incidence of long-term blindness and effectiveness of dexamethasone in avoiding blindness.

Effect of dose of behavioral weight loss treatment on glycemic control in adults with prediabetes

OBJECTIVE

This study examined the effects of three doses of behavioral weight loss treatment, compared with a nutrition education control group, on changes in glycemic control in individuals with obesity and prediabetes.

RESEARCH DESIGN AND METHODS

The study included 287 adults (77% female, 81% White; mean (SD) age=54.1 (10.5) years, body mass index=36.3 (3.9) kg/m², and hemoglobin A1c (HbA1c)=5.9 (0.2%)). Participants were randomized to one of three behavioral treatment doses (high=24 sessions, moderate=16 sessions, or low=8 sessions) or to an education group (control=8 sessions). Changes in HbA1c, fasting glucose, and body weight were assessed from baseline to 6 months.

RESULTS

Mean (99.2% credible interval (CI)) reductions in HbA1c were 0.11% (0.07% to 0.16%), 0.08% (0.03% to 0.13%), 0.03% (-0.01% to 0.07%), and 0.02% (-0.02% to 0.07%), for the high, moderate, low, and control conditions, respectively. Mean (CI) reductions in fasting blood glucose were 0.26 mmol/L (0.14 to 0.39), 0.09 mmol/L (0 to 0.19), 0.01 mmol/L (-0.07 to 0.09), and 0.04 mmol/L (-0.03 to 0.12) for the high, moderate, low, and control conditions, respectively. The high-dose treatment produced significantly greater reductions in HbA1c and fasting blood glucose than the low-dose and control conditions (posterior probabilities (pp)<0.001); no other significant between-group differences were observed. Mean (CI) reductions in body weight were 10.91 kg (9.30 to 12.64), 10.08 kg (8.38 to 11.72), 6.35 kg (5.19 to 7.69), and 3.82 kg (3.04 to 4.54) for the high, moderate, low, and control conditions, respectively. All between-group differences in 6-month weight change were significant (pps<0.001) except for the high-dose versus moderate-dose comparison.

CONCLUSION

For adults with obesity and prediabetes a high dose of behavioral treatment involving 24 sessions over 6 months may be needed to optimize improvements in glycemic control.

TRIAL REGISTRATION NUMBER

NCT00912652.

Economic Costs Attributable to Diabetes in Each U.S. State

OBJECTIVE

To estimate direct medical and indirect costs attributable to diabetes in each U.S. state in total and per person with diabetes.

RESEARCH DESIGN AND METHODS

We used an attributable fraction approach to estimate direct medical costs using data from the 2013 State Health Expenditure Accounts, 2013 Behavioral Risk Factor Surveillance System, and the Centers for Medicare & Medicaid Services' 2013-2014 Minimum Data Set. We used a human capital approach to estimate indirect costs measured by lost productivity from morbidity (absenteeism, presenteeism, lost household productivity, and inability to work) and premature mortality, using the 2008-2013 National Health Interview Survey, 2013 daily housework value data, 2013 mortality data from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research, and mean wages from the 2014 Bureau of Labor Statistics. Costs were adjusted to 2017 U.S. dollars.

RESULTS

The estimated median state economic cost was $5.9 billion, ranging from $694 million to $55.5 billion, in total and $18,248, ranging from $15,418 to $30,915, per person with diabetes. The corresponding estimates for direct medical costs were $2.8 billion (range $0.3-22.9) and $8,544 (range $6,591-12,953) and for indirect costs were $3.0 billion (range $0.4-32.6) and $9,672 (range $7,133-17,962). In general, the estimated state median indirect costs resulting from morbidity were larger than costs from mortality both in total and per person with diabetes.

CONCLUSIONS

Economic costs attributable to diabetes were large and varied widely across states. Our comprehensive state-specific estimates provide essential information needed by state policymakers to monitor the economic burden of the disease and to better plan and evaluate interventions for preventing type 2 diabetes and managing diabetes in their states.

Assessing the potential return on investment of the proposed UK NHS diabetes prevention programme in different population subgroups: an economic evaluation

OBJECTIVES

To evaluate potential return on investment of the National Health Service Diabetes Prevention Programme (NHS DPP) in England and estimate which population subgroups are likely to benefit most in terms of cost-effectiveness, cost-savings and health benefits.

DESIGN

Economic analysis using the School for Public Health Research Diabetes Prevention Model.

SETTING

England 2015-2016.

POPULATION

Adults aged ≥16 with high risk of type 2 diabetes (HbA1c 6%-6.4%). Population subgroups defined by age, sex, ethnicity, socioeconomic deprivation, baseline body mass index, baseline HbA1c and working status.

INTERVENTIONS

The proposed NHS DPP: an intensive lifestyle intervention focusing on dietary advice, physical activity and weight loss. Comparator: no diabetes prevention intervention.

MAIN OUTCOME MEASURES

Incremental costs, savings and return on investment, quality-adjusted life-years (QALYs), diabetes cases, cardiovascular cases and net monetary benefit from an NHS perspective.

RESULTS

Intervention costs will be recouped through NHS savings within 12 years, with net NHS saving of £1.28 over 20 years for each £1 invested. Per 100 000 DPP interventions given, 3552 QALYs are gained. The DPP is most cost-effective and cost-saving in obese individuals, those with baseline HbA1c 6.2%-6.4% and those aged 40-74. QALY gains are lower in minority ethnic and low socioeconomic status subgroups. Probabilistic sensitivity analysis suggests that there is 97% probability that the DPP will be cost-effective within 20 years. NHS savings are highly sensitive to intervention cost, effectiveness and duration of effect.

CONCLUSIONS

The DPP is likely to be cost-effective and cost-saving under current assumptions. Prioritising obese individuals could create the most value for money and obtain the greatest health benefits per individual targeted. Low socioeconomic status or ethnic minority groups may gain fewer QALYs per intervention, so targeting strategies should ensure the DPP does not contribute to widening health inequalities. Further evidence is needed around the differential responsiveness of population subgroups to the DPP.