Systematic review and overview of health economic evaluation models in obesity prevention and therapy

Valuing behavioral interventions for obesity reduction: A scoping review of economic models

Policymakers require health economic modeling to guide their decision-making over the choice of interventions for obesity. This scoping review was undertaken to report on the health economic models in use for estimating the value of behavioral interventions (individual or population level) for obesity reduction. Electronic databases (MEDLINE, Embase, PsycINFO, EconLit, and Web of Science) were searched for publications meeting inclusion criteria from January 2015 to May 2023. Seventy-three studies were included, using 44 health economic models between them. When considered against the expert recommendations for modeling of this type, only four models (9%) met all five key elements. The element most commonly unfulfilled was the use of a microsimulation modeling approach (41%, n = 18), followed by model validation (46%, n = 20). A majority of models met each of the other elements: use of a lifetime horizon (59%, n = 26), inclusion of key health events (66%, n = 29), and a risk equation approach to event simulation (71%, n = 31). In addition, under half of the studies considered health inequalities in their reporting. Continued proliferation of models with inadequate time horizons, breadth of obesity-related health conditions, and perspectives on costs and outcomes risks underestimation of the benefits of longer term interventions and impacts on health inequalities.

Obesity medications: A narrative review of current and emerging agents

The aim of this narrative review is to synthesize the available data describing the efficacy and safety of medications approved for obesity management and to provide an overview of upcoming agents in development. A literature search of PubMed, Medline, and Embase databases identified relevant articles describing medications approved in the U.S., Australia, U.K., and/or Europe. Papers were selected based on relevance and originality, with phase 3 clinical trials and meta-analyses preferentially included. Six medications are widely approved for long-term weight management in conjunction with lifestyle interventions in people with body mass index (BMI) ≥30 ​kg/m2 or BMI ≥27 ​kg/m2 and at least one medical condition related to excess weight. Compared with lifestyle interventions alone, all medications approved for obesity management are more effective for long-term weight loss and improvements in cardiometabolic risk factors. Older obesity medications are associated with mean weight losses in the range of 5-10%. The new generation of agents, including the injectable incretin analogues semaglutide and tirzepatide are associated with sustained mean weight reductions of 15-20%, along with substantial benefits on a range of health outcomes. Several novel agents are under development, with multi-hormone receptor agonists and oral formulations likely to become available in the coming years. As effective treatment options expand, cost and availability will need to be addressed to enable equitable access to treatment. Other important challenges for clinical practice and research include the need for long-term strategies to prevent and manage weight regain and loss of lean muscle and bone mineral density.

Economic Evaluations of Anti-obesity Interventions in Obese Adults: An Umbrella Review

This umbrella review amalgamates the outcomes of economic evaluations pertaining to bariatric surgeries, pharmacotherapy, and gastric balloon for adult obesity treatment. Six databases were systematically searched. The inclusion criteria were established following the Patient/population Intervention Comparison and Outcomes (PICO) statement. Fifteen reviews met all the inclusion criteria. Eight studies focused on surgical interventions, four on pharmacotherapy, and three on both interventions. No systematic review of the economic evaluation of gastric balloons was identified. The majority of reviews advocated bariatric surgery as a cost-effective approach; however, there was discordance in the interpretation of pharmacological cost-effectiveness. Most of the economic evaluations were conducted from the payer and the healthcare system perspectives. We propose that future economic evaluations assessing weight loss interventions in adults adopt a societal perspective and longer-term time horizons.

Does the Structure Matter? An External Validation and Health Economic Results Comparison of Event Simulation Approaches in Severe Obesity

OBJECTIVES

As obesity-associated events impact long-term survival, health economic (HE) modelling is commonly applied, but modelling approaches are diverse. This research aimed to compare the events simulation and the HE outcomes produced by different obesity modelling approaches.

METHODS

An external validation, using the Swedish obesity subjects (SOS) study, of three main structural event modelling approaches was performed: (1) continuous body mass index (BMI) approach; (2) risk equation approach; and (3) categorical BMI-related approach. Outcomes evaluated were mortality, cardiovascular events, and type 2 diabetes (T2D) for both the surgery and the control arms. Concordance between modelling results and the SOS study were investigated by different state-of-the-art measurements, and categorized by the grade of deviation observed (grades 1-4 expressing mild, moderate, severe, and very severe deviations). Furthermore, the costs per quality-adjusted life-year (QALY) gained of surgery versus controls were compared.

RESULTS

Overall and by study arm, the risk equation approach presented the lowest average grade of deviation (overall grade 2.50; control arm 2.25; surgery arm 2.75), followed by the continuous BMI approach (overall 3.25; control 3.50; surgery 3.00) and by the categorial BMI approach (overall 3.63; control 3.50; surgery 3.75). Considering different confidence interval limits, the costs per QALY gained were fairly comparable between all structural approaches (ranging from £2,055 to £6,206 simulating a lifetime horizon).

CONCLUSION

None of the structural approaches provided perfect external event validation, although the risk equation approach showed the lowest overall deviations. The economic outcomes resulting from the three approaches were fairly comparable.

Food addiction among morbidly obese patients: prevalence and links with obesity complications

BACKGROUND

In the context of obesity, little is known about the prevalence of food addiction nor about the phenotype of obese patients with food addiction. Objectives: To assess: (i) the prevalence of food addiction among obese patients eligible for obesity surgery; (ii) the relationship between clinical features and the complications of obesity. Methods: Consecutive patients consulting for the first time were included. The Yale Food Addiction Scale (YFAS) 2.0 questionnaire was used to diagnose food addiction and its severity. Demographics, clinical features, and obesity complications were systematically collected. Statistics: Student's test was used for numerical variables and Chi-square test or Fisher's exact test for categorical variables. Results: A total of 292 patients were included: 79% female, age (mean ± SD) 42.6 ± 13.0 yrs., body mass index (BMI) 43.2 ± 6.8 kg/m². One hundred and eight patients (37%) had food addiction: 58% severe, 33% moderate, 9% mild. Food addiction prevalence was 39% (n = 61/156) among patients eligible for obesity surgery. Food addiction was more frequent among the unemployed, compared to professionally active patients (41.0% vs. 33.5%, p = 0.046). Clinical and metabolic phenotypes and obesity complications were similar between patients with and without food addiction. Conclusion: Food addiction was present in 37% of obese patients, but was not associated with clinical features or obesity complications. Therefore, it should be systemically assessed for appropriate management.

Replication of Published Health Economic Obesity Models: Assessment of Facilitators, Hurdles and Reproduction Success

OBJECTIVES

This research aims to (1) replicate published health economic models, (2) compare reproduced results with original results, (3) identify facilitators and hurdles to model replicability and determine reproduction success, and (4) suggest model replication reporting standards to enhance model reproducibility, in the context of health economic obesity models.

METHODS

Four health economic obesity models simulating an adult UK population were identified, selected for replication, and evaluated using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. Reproduction results were compared to original results, focusing on cost-effectiveness outcomes, and the resulting reproduction success was assessed by published criteria. Replication facilitators and hurdles were identified and transferred into related reporting standards.

RESULTS

All four case studies were state-transition models simulating costs and quality-adjusted life-years (QALYs). Comparing original versus reproduction outcomes, the following deviation ranges were observed: costs - 3.9 to 16.1% (mean over all model simulations 3.78%), QALYs - 3.7 to 2.1% (mean - 0.11%), and average cost-utility ratios - 3.0 to 17.9% (mean 4.28%). Applying different published criteria, an overall reproduction success was observed for three of four models. Key replication facilitators were input data tables and model diagrams, while missing standard deviations and missing formulas for equations were considered as key hurdles.

CONCLUSIONS

This study confirms the feasibility of rebuilding health economic obesity models, but minor to major assumptions were needed to fill reporting gaps. Model replications can help to assess the quality of health economic model documentation and can be used to validate current model reporting practices. Simple changes to actual CHEERS reporting criteria may solve identified replication hurdles.

Modeling Obesity in Norway (The MOON Study): A Decision-Analytic Approach-Prevalence, Costs, and Years of Life Lost

BACKGROUND

Limited knowledge exists on the expected long-term effects and cost-effectiveness of initiatives aiming to reduce the burden of obesity.

AIM

To develop a Norwegian obesity-focused disease-simulation model: the MOON model.

MATERIAL AND METHODS

We developed a Markov model and simulated a Norwegian birth cohort's movement between the health states "normal weight,""overweight,""obese 1,""obese 2," and "dead" using a lifetime perspective. Model input was estimated using longitudinal data from health surveys and real-world data (RWD) from local and national registers (N = 99,348). The model is deterministic and probabilistic and stratified by gender. Model validity was assessed by estimating the cohort's expected prevalence, health care costs, and mortality related to overweight and obesity.

RESULTS

Throughout the cohort's life, the prevalence of overweight increased steadily and stabilized at 45% at 45 y of age. The number of obese 1 and 2 individuals peaked at age 75 y, when 44% of women and 35% of men were obese. The incremental costs per person associated with obesity was highest in older ages and, when accumulated over the lifetime, higher among women (€12,118, €9,495-€15,047) than men (€6,646, €5,252-€10,900). On average, obesity shortened the life expectancy of women/men in the whole cohort by 1.31/1.08 y. The life expectancy for normal-weight women/men at age 30 was 83.31/80.31. The life expectancy was reduced by 1.05/0.65 y if the individual was overweight, obese (2.87/2.71 y), or obese 2 (4.06/4.83 y).

CONCLUSION

The high expected prevalence of obesity in the future will lead to substantial health care costs and large losses in life-years. This underscores the need to implement interventions to reduce the burden of obesity; the MOON model will enable economic evaluations for a wide range of interventions.

Meeting of Minds around Food Addiction: Insights from Addiction Medicine, Nutrition, Psychology, and Neurosciences

This review, focused on food addiction (FA), considers opinions from specialists with different expertise in addiction medicine, nutrition, health psychology, and behavioral neurosciences. The concept of FA is a recurring issue in the clinical description of abnormal eating. Even though some tools have been developed to diagnose FA, such as the Yale Food Addiction Scale (YFAS) questionnaire, the FA concept is not recognized as an eating disorder (ED) so far and is even not mentioned in the Diagnostic and Statistical Manuel of Mental Disorders version 5 (DSM-5) or the International Classification of Disease (ICD-11). Its triggering mechanisms and relationships with other substance use disorders (SUD) need to be further explored. Food addiction (FA) is frequent in the overweight or obese population, but it remains unclear whether it could articulate with obesity-related comorbidities. As there is currently no validated therapy against FA in obese patients, FA is often underdiagnosed and untreated, so that FA may partly explain failure of obesity treatment, addiction transfer, and weight regain after obesity surgery. Future studies should assess whether a dedicated management of FA is associated with better outcomes, especially after obesity surgery. For prevention and treatment purposes, it is necessary to promote a comprehensive psychological approach to FA. Understanding the developmental process of FA and identifying precociously some high-risk profiles can be achieved via the exploration of the environmental, emotional, and cognitive components of eating, as well as their relationships with emotion management, some personality traits, and internalized weight stigma. Under the light of behavioral neurosciences and neuroimaging, FA reveals a specific brain phenotype that is characterized by anomalies in the reward and inhibitory control processes. These anomalies are likely to disrupt the emotional, cognitive, and attentional spheres, but further research is needed to disentangle their complex relationship and overlap with obesity and other forms of SUD. Prevention, diagnosis, and treatment must rely on a multidisciplinary coherence to adapt existing strategies to FA management and to provide social and emotional support to these patients suffering from highly stigmatized medical conditions, namely overweight and addiction. Multi-level interventions could combine motivational interviews, cognitive behavioral therapies, and self-help groups, while benefiting from modern exploratory and interventional tools to target specific neurocognitive processes.

Lifestyle information and access to a commercial weight management group to promote maternal postnatal weight management and positive lifestyle behaviour: the SWAN feasibility RCT

Background

Increasing numbers of UK women have overweight or obese body mass index scores when they become pregnant, or gain excessive weight in pregnancy, increasing their risk of adverse outcomes. Failure to manage postnatal weight is linked to smoking, non-healthy dietary choices, lack of regular exercise and poorer longer-term health. Women living in areas of higher social deprivation are more likely to experience weight management problems postnatally.

Objectives

The objectives were to assess the feasibility of conducting a definitive randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of lifestyle information and access to a commercial weight management group focusing on self-monitoring, goal-setting and motivation to achieve dietary change commencing 8–16 weeks postnatally to achieve and maintain weight management and positive lifestyle behaviour.

Design

The design was a randomised two-arm feasibility trial with a nested mixed-methods process evaluation.

Setting

The setting was a single centre in an inner city setting in the south of England.

Participants

Participants were women with body mass index scores of > 25 kg/m2 at antenatal ‘booking’ and women with normal body mass index scores (18.0–24.9 kg/m2) at antenatal booking who developed excessive gestational weight gain as assessed at 36 weeks’ gestation.

Main outcome measures

Recruitment, retention, acceptability of trial processes and identification of relevant economic data were the feasibility objectives. The proposed primary outcome was difference between groups in weight at 12 months postnatally, expressed as percentage weight change and weight loss from antenatal booking. Other proposed outcomes included assessment of diet, physical activity, smoking, alcohol consumption, body image, maternal esteem, mental health, infant feeding and NHS costs.

Results

Most objectives were achieved. A total of 193 women were recruited, 98 allocated to the intervention arm and 95 to the control arm. High follow-up rates (> 80%) were achieved to 12 months. There was an 8.8% difference in weight loss at 12 months between women allocated to the intervention arm and women allocated to the control arm (13.0% vs. 4.2%, respectively; p = 0.062); 47% of women in the intervention arm attended at least one weight management session, with low risk of contamination between arms. The greatest benefit was among women who attended ≥ 10 sessions. Barriers to attending sessions included capability, opportunity and motivation issues. Data collection tools were appropriate to support economic evaluation in a definitive trial, and economic modelling is feasible to quantify resource impacts and outcomes not directly measurable within a trial.

Limitations

The trial recruited from only one site. It was not possible to recruit women with normal body mass index scores who developed excessive pregnancy weight gain.

Conclusions

It was feasible to recruit and retain women with overweight or obese body mass index scores at antenatal booking to a trial comparing postnatal weight management plus standard care with standard care only and collect relevant data to assess outcomes. Approaches to recruit women with normal body mass index scores who gain excessive gestational weight need to be considered. Commercial weight management groups could support women’s weight management as assessed at 12 months postnatally, with probable greater benefit from attending ≥ 10 sessions. Process evaluation findings highlighted the importance of providing more information about the intervention on trial allocation, extended duration of time to commence sessions following birth and extended number of sessions offered to enhance uptake and retention. Results support the conduct of a future randomised controlled trial.

Trial registration

Current Controlled Trials ISRCTN39186148.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 8, No. 9. See the NIHR Journals Library website for further project information.

A Systematic Review of Methods to Predict Weight Trajectories in Health Economic Models of Behavioral Weight-Management Programs: The Potential Role of Psychosocial Factors

Objectives. There is limited evidence on the long-term effectiveness of behavioral weight-management interventions, and thus, when conducting health economic modeling, assumptions are made about weight trajectories. The aims of this review were to examine these assumptions made about weight trajectories, the evidence sources used to justify them, and the impact of assumptions on estimated cost-effectiveness. Given the evidence that some psychosocial variables are associated with weight-loss trajectories, we also aimed to examine the extent to which psychosocial variables have been used to estimate weight trajectories and whether psychosocial variables were measured within cited evidence sources. Methods. A search of databases (Medline, PubMed, Cochrane, NHS Economic Evaluation, Embase, PSYCinfo, CINAHL, EconLit) was conducted using keywords related to overweight, weight-management, and economic evaluation. Economic evaluations of weight-management interventions that included modeling beyond trial data were included. Results. Within the 38 eligible articles, 6 types of assumptions were reported (weight loss maintained, weight loss regained immediately, linear weight regain, subgroup-specific trajectories, exponential decay of effect, maintenance followed by regain). Fifteen articles cited at least 1 evidence source to support the assumption reported. The assumption used affected the assessment of cost-effectiveness in 9 of the 19 studies that tested this in sensitivity analyses. None of the articles reported using psychosocial factors to estimate weight trajectories. However, psychosocial factors were measured in evidence sources cited by 11 health economic models. Conclusions. Given the range of weight trajectories reported and the potential impact on funding decisions, further research is warranted to investigate how psychosocial variables measured in trials can be used within health economic models to simulate heterogeneous weight trajectories and potentially improve the accuracy of cost-effectiveness estimates.

The potential for long-term cost-effectiveness of obesity prevention interventions in the early years of life

BACKGROUND

Early childhood obesity prevention is gaining increasing importance, as the prevalence of children with overweight and obesity aged 5 years and under increases worldwide. Along with understanding the effectiveness of obesity interventions, it is important to understand the cost-effectiveness of interventions over time.

OBJECTIVES

To estimate the long-term health benefits and health care cost-savings of reductions in BMI for the Australian population of children aged between 2 and 5 years.

METHODS

A proportional multistate, multiple cohort lifetable model estimated the health benefits and health care cost-savings related to hypothetical reductions in BMI, informed by a scoping review of systematic reviews reporting the effectiveness of obesity prevention interventions in preschool aged children.

RESULTS

Results suggest significant potential for cost-effectiveness of obesity prevention interventions in preschool-aged children if intervention effect can be maintained. A relatively small population level reduction in BMI z-score (-0.13 BMIz) in children aged 2 to 5 years would result in 36 496 health-adjusted life years saved (95% uncertainty interval [UI], 30 283-42 945) and health care cost-savings of approximately $301 million (95% UI $234 million-$369 million) if modelled over the lifetime.

CONCLUSIONS

Scenario results highlight the importance of obesity intervention in the early years of life.

A New Model for Evaluation of Interventions to Prevent Obesity in Early Childhood

Background: Childhood obesity is a serious public health issue. In Australia, 1 in 4 children is already affected by overweight or obesity at the time of school entry. Governments around the world have recognized this problem through investment in the prevention of pediatric obesity, yet few interventions in early childhood have been subjected to economic evaluation. Information on cost-effectiveness is vital to decisions about program implementation. A challenge in evaluating preventive interventions in early childhood is to capture long-term costs and outcomes beyond the duration of an intervention, as the benefits of early obesity prevention will not be realized until some years into the future. However, decisions need to be made in the present, and modeling is one way to inform such decisions. Objective: To describe the conceptual structure of a new health economic model (the Early Prevention of Obesity in CHildhood (EPOCH) model) for evaluating childhood obesity interventions; and to validate the epidemiologic predictions. Methods and Results: We use an individual-level (micro-simulation) method to model BMI trajectories and the progression of obesity from early childhood to adolescence. The equations predicting individual BMI change underpinning our model were derived from data from the population-representative study, the Longitudinal Study of Australian Children (LSAC). Our approach is novel because it will account for costs and benefits accrued throughout childhood and adolescence. As a first step to validate the epidemiological predictions of the model, we used input data representing over 250,000 children aged 4/5 years, and simulated BMI and obesity trajectories until adolescence. Simulated mean BMI and obesity prevalence for boys and girls were verified by nationally-representative data on children at 14/15 years of age. Discussion: The EPOCH model is epidemiologically sound in its prediction of both BMI trajectories and prevalence of obesity for boys and girls. Future developments of the model will include socio-economic position and will incorporate the impacts of obesity on healthcare costs. The EPOCH model will help answer: when is it best to intervene in childhood; what are the most cost-effective approaches and which population groups will benefit most from interventions.

Event simulation and external validation applied in published health economic models for obesity: a systematic review

INTRODUCTION

This study aims to determine methodological variations in the event simulation approaches of published health economic decision models, in the field of obesity, and to investigate whether their predictiveness and validity were investigated via external event validation techniques, which investigate how well the model reproduces reality.

AREAS COVERED

A systematic review identified a total of 87 relevant papers, of which 72 that simulated obesity-associated events were included. Most frequently simulated events were coronary heart disease (≈ 83%), type 2 diabetes (≈ 74%), and stroke (≈ 66%). Only for ten published model-based health economic assessments in obesity an external event validation was performed (14%; 10 of 72), and only for one the predictiveness and validity of the event simulation was investigated in a cohort of obese subjects.

EXPERT COMMENTARY

We identified a wide range of obesity related event simulation approaches. Published obesity models lack information on the predictive quality and validity of the applied event simulation approaches. Further work on comparing and validating these event simulation approaches is required to investigate their predictiveness and validity, which will offer guidance future modelling in the field of obesity.

A systematic review on economic evaluations of school-based lifestyle interventions targeting weight-related behaviours among 4-12 year olds: Issues and ways forward

Current guidelines for economic evaluations do not provide specific recommendations for the evaluation of school-based lifestyle interventions. This study examined and discussed the key aspects in the design of economic evaluations on school-based interventions targeting weight-related behaviours among 4-12 year olds. The PubMed and CRD databases (NHS EED) were searched. Grey literature was identified from reference lists and websites of relevant organizations. Full economic evaluations on school-based interventions targeting physical activity, sedentariness, or diet were selected. Key aspects included the objective, audience, intervention, comparator, population, type of analysis, perspective, costs, outcomes, and time horizon. Information was also extracted on measuring and valuing costs and outcomes, linking and extrapolating outcomes, and the maintenance of intervention effects. The 23 included studies reported on cost-effectiveness (CEAs) (N = 12), cost-utility (CUAs) (N = 9), social cost benefit (SCBA) (N = 2), and social return on investment (SROI) (N = 1) analysis. The usual practice comparator was generally not clearly defined. The SROI analysis was the single study that included outcomes in other persons than the child. Healthcare costs (N = 14), productivity costs (N = 4), and costs to the household (N = 3), or education (N = 2) sector were examined. The outcome in trial-based CEAs consisted of a variety of weight-related measures. Seven distinctive models were used to extrapolate health and/or productivity costs. To enhance the usefulness of economic evaluations on school-based lifestyle interventions in allocating public health budgets, transparent reporting on key aspects, broadening the scope of economic evaluations, and standardizing the measurement, valuation, and extrapolation of costs and outcomes should be improved. This study was conducted in Maastricht, the Netherlands.

Cost effectiveness and return on investment of a scalable community weight loss intervention

This study assessed the lifetime health and economic consequences of an efficacious scalable community weight loss program for overweight and obese adults. We applied a state-transition Markov model to project lifetime economic outcome (US dollar) and the degree of disease averted as a result of a weight loss intervention, compared with no intervention, from a payer perspective. Effect sizes of the intervention on weight loss, by sex, race and ethnicity, and body mass index (BMI) of participants, were derived from a 12-month community program. Relative risk of diseases across BMI levels and other parameters were informed by the literature. A return on investment (ROI) analysis was conducted to present the overall cost-benefit of the program. Simulation results showed that among 33,656 participants and at a cost of $2.88 million, the program was predicted to avert (with a corresponding estimated medical costs saved of) 78 cases of coronary heart disease ($28 million), 9 cases of strokes ($971,832), 92 cases of type 2 diabetes ($24 million), 1 case of colorectal cancer ($357,022), and 3 cases of breast cancer ($483,259) over the participant lifetime. The estimated medical costs saved per participant was $1403 ($1077 of African American men and $1532 of Hispanic men), and the ROI was $16.7 ($12.8 for African American men and $18.3 for Hispanic men) for every $1 invested. We concluded that a scalable efficacious community weight loss program provides a cost-effective approach with significant ROI, which will assist informed decisions for future adoption and dissemination.

Phenolic compounds as natural and multifunctional anti-obesity agents: A review

Prevalence of obesity worldwide has reached pandemic proportions. Despite the increasing evidence in the implication of phenolic compounds in obesity management, the real effect is not completely understood. The available in vitro and in vivo studies have demonstrated the implication of phenolic compounds in: lowering food intake, decreasing lipogenesis, increasing lipolysis, stimulating fatty acids β-oxidation, inhibiting adipocyte differentiation and growth, attenuating inflammatory responses and suppress oxidative stress. This review encompasses the most recent evidence in the anti-obesity effect of phenolic compounds from plants to different nutraceuticals and functional foods based on the in vitro, in vivo and clinical studies. For that, this review has been focused on popular plant-based products highly consumed today such as cocoa, cinnamon, and olive oil, beverages such as red wine, tea (green, white and black tea) and Hibiscus sabdariffa L. tea, among others.