Cost-effectiveness of pharmacological anti-obesity treatments: a systematic review

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.

Pharmacoeconomic evaluation of anti-obesity drugs for chronic weight management: a systematic review of literature

Introduction

Pharmacological therapy is recommended as a second-line alternative to reverse obesity. Currently, five anti-obesity drugs (AODs) have been approved by the U.S. Food and Drug Administration (FDA) for chronic weight management. The aim of this paper is to investigate the pharmacoeconomic evaluation of AODs through a systematic review with a special focus on methodological considerations.

Methods

We searched the general and specific databases to identify the primary pharmacoeconomic evaluation of AODs.

Results

A total of 18 full-text articles and three conference abstracts were included in this review. Most of the economic assessments were still about Orlistat. And the observations we could make were consistent with the previous systematic review. A few studies were on the combined therapies (i.e. PHEN/TPM ER and NB ER) compared to different comparators, which could hardly lead to a generalized summary of the cost-effectiveness. Most recently, pharmacoeconomic evidence on the newest GLP 1 RA approved for the indication of obesity or obesity with at least one comorbidity emerged gradually. Modelling-based cost-utility analysis is the major type of assessment method. In the modelling studies, a manageable number of the key health states and the state transitions were structured to capture the disease progression. In particular, the principal structure of the decision model adopted in the three studies on the newly approved drug was nearly the same, which enables more in-depth comparisons and generalizations of the findings.

Conclusion

This study provided an up-to-date overview of the strengths and areas for improvement in the methodological design of the pharmacoeconomic evaluation of the licensed drugs for chronic weight management. Future modelling evaluations would benefit from a better understanding of the long-term weight loss effects of the current therapeutic options and the weight rebound process after the discontinuation of treatment.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022302648, identifier CRD42022302648.

The Relative Value of Anti-Obesity Medications Compared to Similar Therapies

Purpose

To demonstrate a need for improved health insurance coverage for anti-obesity medications (AOMs) by comparing clinical and economic benefits of obesity treatments to covered medications for selected therapeutic areas.

Methods

Using a grey literature search, we identified and prioritized therapeutic areas and treatment analogues for comparison to obesity. A targeted literature review identified clinical and economic outcomes research across the therapeutic area analogues. Associated comorbidities, clinical evidence, indirect costs (ie, absenteeism and productivity loss), and direct medical costs were evaluated to determine the relative value of treating obesity.

Results

Four therapeutic areas/treatment analogues were selected for comparison to obesity: smoking cessation (varenicline), daytime sleepiness (modafinil), migraines (erenumab), and fibromyalgia (pregabalin). Obesity was associated with 17 comorbidities, more than migraine (9), smoking (8), daytime sleepiness (5), and fibromyalgia (2). Economic burden was greatest for obesity, followed by smoking, with yearly indirect and direct medical costs totaling $676 and $345 billion, respectively. AOMs resulted in cost savings of $2586 in direct medical costs per patient per year (PPPY), greater than that for varenicline at $930 PPPY, modafinil at $1045 PPPY, and erenumab at $468 PPPY; pregabalin utilization increased costs by $924 PPPY. AOMs were covered by 10-16% of United States health insurance plans, compared to 45-59% for the four comparators.

Conclusion

Compared to four therapeutic analogues, obesity represented the highest economic burden and was associated with more comorbidities. AOMs provide greater cost savings compared to selected analogues. However, AOMs have limited formulary coverage. Improved coverage of AOMs may increase access to these treatments and may help address the clinical and economic burden associated with obesity and its comorbidities.

Do Centers for Medicare and Medicaid Services Quality Measures Reflect Cost-Effectiveness Evidence?

OBJECTIVES

Despite its importance of quality measures used by the Centers for Medicare and Medicaid Services, the underlying cost-effectiveness evidence has not been examined. This study aimed to analyze cost-effectiveness evidence associated with the Centers for Medicare and Medicaid Services quality measures.

METHODS

After classifying 23 quality measures with the Donabedian's structure-process-outcome quality of care model, we identified cost-effectiveness analyses (CEAs) relevant to these measures from the Tufts Medical Center CEA Registry based on the PICOTS (population, intervention, comparator, outcome, time horizon, and setting) framework. We then summarized available incremental cost-effectiveness ratios (ICERs) to determine the cost-effectiveness of the quality measures.

RESULTS

The 23 quality measures were categorized into 14 process, 7 outcome, and 2 structure measures. Cost-effectiveness evidence was only available for 8 of 14 process measures. Two measures (Tobacco Screening and Hemoglobin bA1c Control) were cost-saving and quality-adjusted life-years (QALYs) improving, and 5 (Depression Screening, Influenza Immunization, Colon Cancer Screening, Breast Cancer Screening, and Statin Therapy) were highly cost-effective (median ICER ≤ $50 000/QALY). The remaining measure (Fall Screening) had a median ICER of $120 000/QALY. No CEAs were available for 15 measures: 10 defined by subjective patient ratings and 5 employed outcome measures without specifying an intervention or process.

CONCLUSIONS

When relevant CEAs were available, cost-effectiveness evidence was consistent with quality measures (measures were cost-effective). Nevertheless, most quality measures were based on subjective ratings or outcome measures, posing a challenge in identifying supporting economic evidence. Refining and aligning quality measures with cost-effectiveness evidence can help further improve healthcare efficiency by demonstrating that they are good indicators of both quality and cost-effectiveness of care.

Incremental cost-effectiveness of evidence-based non-surgical weight loss strategies

Recent medical advancements have led to new modes of treatment for non-surgical weight loss, including several new medications. Our aim was to conduct an incremental cost-effectiveness analysis for all commercially available, evidence-based non-surgical weight loss interventions for people with excess weight. We identified interventions through a systematic review of randomized controlled trials that reported weight loss 12 months from baseline. We then meta-analysed the results, sourced costs and performed an incremental cost-effectiveness analysis from the payer perspective. Cost-effectiveness was presented in terms of cost per kilogram lost and quality-adjusted life years (QALY) gained. We further performed sensitivity analyses on costs and duration of benefits, and a probabilistic sensitivity analysis. Ten interventions were identified for inclusion: six pharmaceutical products (Alli, Xenical, Qsymia, Contrave, Belviq and Saxenda), two lifestyle modification programmes (Weight Watchers Meetings and Online), one food replacement and lifestyle programme (Jenny Craig) and one intragastric balloon system (Orbera). At an incremental cost-effectiveness ratio of $30 071 per additional QALY gained, only Weight Watchers Meetings was cost-effective. Sensitivity analyses revealed that for the medications to become incrementally cost-effective, costs would have to decrease by as much as 91%. Results are highly dependent on duration that benefits are maintained. Despite several newly available interventions, Weight Watchers Meetings is currently the only evidence-based, commercially available, cost-effective option for non-surgical weight loss. Other interventions, specifically medications, are more effective but priced too high to be cost-effective.

Is Doctor Referral to a Low-Energy Total Diet Replacement Program Cost-Effective for the Routine Treatment of Obesity?

OBJECTIVE

The study objective was to estimate the cost-effectiveness of a commercially provided low-energy total diet replacement (TDR) program compared with nurse-led behavioral support.

METHODS

A multistate life table model and the weight reduction observed in a randomized controlled trial were used to evaluate the quality-adjusted life-years and direct health care costs (in United Kingdom 2017 prices) over a lifetime with TDR versus nurse-led support in adults who had obesity, assuming that (i) weight returns to baseline over 5 years and (ii) a 1-kg weight loss is maintained after 5 years following TDR.

RESULTS

The per-person costs of the TDR and nurse-led programs were £796 and £34, respectively. The incremental cost-effectiveness ratio of TDR was £12,955 (95% CI: £8,082-£17,827) assuming that all weight lost is regained and £3,203 (£2,580-£3,825) assuming that a 1-kg weight loss is maintained after 5 years. TDR was estimated to be more cost-effective (i.e., lower incremental cost-effectiveness ratios) in older adults and those with a higher BMI, with little difference by gender.

CONCLUSIONS

At current retail prices and with plausible long-term weight regain trajectories, TDR is projected to be cost-effective in adults with obesity and could be considered as an option to treat obesity in routine health care settings.

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.

Pilot survey of a novel incentive to promote healthy behavior among school children and their parents

Reversing the obesity epidemic has been a persistent global public health challenge, particularly among low socioeconomic status populations and racial/ethnic minorities. We developed a novel concept of community-based incentives to approach this problem in such communities. Applying this concept, we proposed a school intervention to promote obesity prevention in the U.S. We conducted a pilot survey to explore attitudes towards this future intervention. The survey was collected as a nonprobability sample (N = 137 school-aged children (5-12 years)) in northern California in July 2013. We implemented multivariable logistic regression analyses where the dependent variable indicated the intention to participate in the future intervention. The covariates included the body mass index (BMI) based weight categories, demographics, and others. We found that the future intervention is expected to motivate generally-high-risk populations (such as children and parents who have never joined a past health-improvement program compared to those who have completed a past health-improvement program (the odds-ratio (OR) = 5.84, p < 0.05) and children with an obese/overweight parent (OR = 2.72, p < 0.05 compared to those without one)) to participate in future obesity-prevention activities. Our analyses also showed that some subgroups of high-risk populations, such as Hispanic children (OR = 0.27, p < 0.05) and children eligible for a free or reduced price meal program (OR = 0.37, p < 0.06), remain difficult to reach and need an intensive outreach activity for the future intervention. The survey indicated high interest in the future school intervention among high-risk parents who have never joined a past health-improvement program or are obese/overweight. These findings will help design and implement a future intervention.

Obesity coverage gap: Consumers perceive low coverage for obesity treatments even when workplace wellness programs target BMI

OBJECTIVE

Evidence-based obesity treatments, such as bariatric surgery, are not considered essential health benefits under the Affordable Care Act. Employer-sponsored wellness programs with incentives based on biometric outcomes are allowed and often used despite mixed evidence regarding their effectiveness. This study examines consumers' perceptions of their coverage for obesity treatments and exposure to workplace wellness programs.

METHODS

A total of 7,378 participants completed an online survey during 2015-2016. Respondents answered questions regarding their health coverage for seven medical services and exposure to employer wellness programs that target weight or body mass index (BMI). Using χ² tests, associations between perceptions of exposure to employer wellness programs and coverage for medical services were examined. Differences between survey years were also assessed.

RESULTS

Most respondents reported they did not have health coverage for obesity treatments, but more of the respondents with employer wellness programs reported having coverage. Neither the perception of coverage for obesity treatments nor exposure to wellness programs increased between 2015 and 2016.

CONCLUSIONS

Even when consumers have exposure to employer wellness programs that target BMI, their health insurance often excludes obesity treatments. Given the clinical and cost-effectiveness of such treatments, reducing that coverage gap may mitigate obesity's individual- and population-level effects.

New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What Has Been Investigated, and What Is in the Pipeline?

A wide range of support is available to help smokers to quit and to aid attempts at harm reduction, including three first-line smoking cessation medications: nicotine replacement therapy, varenicline and bupropion. Despite the efficacy of these, there is a continual need to diversify the range of medications so that the needs of tobacco users are met. This paper compares the first-line smoking cessation medications with (1) two variants of these existing products: new galenic formulations of varenicline and novel nicotine delivery devices; and (2) 24 alternative products: cytisine (novel outside Central and Eastern Europe), nortriptyline, other tricyclic antidepressants, electronic cigarettes, clonidine (an anxiolytic), other anxiolytics (e.g. buspirone), selective serotonin reuptake inhibitors, supplements (e.g. St John's wort), silver acetate, Nicobrevin, modafinil, venlafaxine, monoamine oxidase inhibitors (MAOIs), opioid antagonists, nicotinic acetylcholine receptor (nAChR) antagonists, glucose tablets, selective cannabinoid type 1 receptor antagonists, nicotine vaccines, drugs that affect gamma-aminobutyric acid (GABA) transmission, drugs that affect N-methyl-D-aspartate (NMDA) receptors, dopamine agonists (e.g. levodopa), pioglitazone (Actos; OMS405), noradrenaline reuptake inhibitors and the weight management drug lorcaserin. Six 'ESCUSE' criteria-relative efficacy, relative safety, relative cost, relative use (overall impact of effective medication use), relative scope (ability to serve new groups of patients) and relative ease of use-are used. Many of these products are in the early stages of clinical trials; however, cytisine looks most promising in having established efficacy and safety with low cost. Electronic cigarettes have become very popular, appear to be efficacious and are safer than smoking, but issues of continued dependence and possible harms need to be considered.

Phenylbutazone, a New Long-Acting Agent that can Improve the Peptide Pharmacokinetic Based on Serum Albumin as a Drug Carrier

As a NPY-2 receptor agonist, PYY24-36- Leu31 is reported to suppress appetite and has a potential in obesity treatment, but its short half-life limits the clinical application. The use of chemical modification to improve interactions with human serum albumin (HSA) is an effective strategy for prolonging the half-lives of peptide analogues. So based on the characteristics that phenylbutazone has a good combination with HSA, we selected a proper linker to link with PYY24-36 -Leu31 to create long-acting and highly biologically active PYY24-36 -Leu31 conjugates, and successfully find a novel, long-acting PYY24-36 -Leu31 conjugate 8 that, when dosed every other day in diet induce obese (DIO) mice for 2 weeks, results in a significant reduction in food intake and body weight and improvement in blood parameter and hepatic steatosis.

4-Year Cost Trajectories in Real-World Patients Matched to the Metabolic Profiles of Trial Subjects Before/After Treatment with Phentermine-Topiramate

Objective

Our objective was to estimate 4-year healthcare costs associated with the metabolic profile of patients before and after 1 year of treatment with phentermine (15 mg) and topiramate extended-release (92 mg) [phentermine-topiramate ER].

Design and Methods

Using a medical records database, we created two patient cohorts reflecting metabolic profiles of subjects before and after phentermine-topiramate ER therapy during the 1-year CONQUER trial. We matched database patients with trial subjects by age, sex, body mass index (BMI), and hypertension, glycemic, and triglyceride status. We collected real-world data on emergency department and outpatient visits, hospitalizations, and drug prescriptions over 4 years, linking them to reimbursements to estimate US private insurance costs for post-trial (n = 2295) versus pre-trial intention-to-treat (ITT) patients (n = 2295). Secondary analysis assessed responders (completers losing ≥5 % body weight [n = 1285]).

Results

Over 4 years, the mean cost per patient in the post- versus pre-trial ITT-group was $US32,432 versus $US34,725 (mean difference −2292; 95 % confidence interval [CI] –4776 to 209). In responders, corresponding costs were $US30,558 versus $US33,936 (mean difference –3378; 95 % CI –6496 to –464). Costs for post- versus pre-trial responders were lower for outpatient visits, emergency visits, and medications (all P < 0.05).

Conclusion

Excluding treatment cost and potential side effects, patients matched to profiles of phentermine-topiramate ER responders had lower costs than patients matched to pre-treatment profiles.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0021-x) contains supplementary material, which is available to authorized users.

Association between obesity and prescribed medication use in England

We investigate the association between obesity and use of prescribed medications in England. Data were taken from fourteen rounds of the Health Survey for England (1999-2012), which has measures of current prescribed medication use based on therapeutic classifications in the British National Formulary, and nurse-measured height and weight. We find that obesity has a statistically significant and positive association with use of a range of medicines for managing diseases associated with obesity. The mean probability of using any type of medication is 0.40 in those of normal weight, 0.44 in the overweight, 0.52 in obesity class I and 0.60 in obesity class II/III. Significant positive associations were found between obesity and the use of medication for diseases of the cardiovascular system, gastrointestinal system, respiratory system, and central nervous system, as well as for infections, endocrine system disorders, gynaecological/urinary disorders and musculoskeletal and joint disorders. Use of anti-obesity medication is low, even among those with class II/III obesity.

Economics of obesity--learning from the past to contribute to a better future

The discipline of economics plays a varied role in informing the understanding of the problem of obesity and the impact of different interventions aimed at addressing it. This paper discusses the causes of the obesity epidemic from an economics perspective, and outlines various justifications for government intervention in this area. The paper then focuses on the potential contribution of health economics in supporting resource allocation decision making for obesity prevention/treatment. Although economic evaluations of single interventions provide useful information, evaluations undertaken as part of a priority setting exercise provide the greatest scope for influencing decision making. A review of several priority setting examples in obesity prevention/treatment indicates that policy (as compared with program-based) interventions, targeted at prevention (as compared with treatment) and focused “upstream” on the food environment, are likely to be the most cost-effective options for change. However, in order to further support decision makers, several methodological advances are required. These include the incorporation of intervention costs/benefits outside the health sector, the addressing of equity impacts, and the increased engagement of decision makers in the priority setting process.

Do we need anti-obesity drugs?

The increasing global prevalence of obesity urgently requires an implementation of efficient preventive and therapeutic measures. Weight loss and its maintenance should be considered one of the most important strategies to reduce the incidence of obesity-related co-morbidities such as diabetes and cardiovascular diseases. Lifestyle modification focused on diet and physical activity represents the essential component of any kind of weight management. However, only an intensive lifestyle intervention can be efficient in terms of long-term weight loss. Anti-obesity drugs affect different targets in the central nervous system or peripheral tissues and improve regulatory and metabolic disturbances that contribute to the development of obesity. Anti-obesity medications provide modest additional fat loss to that achieved by lifestyle modification alone, reduce visceral fat stores, improve programme adherence, weight loss maintenance, diminish obesity-related health risks and improve a quality of life. Anti-obesity drugs do play a role in weight management. Their replacement with placebo is followed by weight regain. Due to adverse events, several anti-obesity drugs were withdrawn from the market over the past few years and currently only orlistat remains available for long-term obesity management. Drug withdrawals, failure of clinical trials with several new anti-obesity compounds as well as inappropriate demands of drug regulating agencies concerning the study protocol led to scepticism about the perspectives in the pharmacotherapy of obesity. However, recently developed anti-obesity medications such as gut hormone analogues and drug combinations provided encouraging results in terms of weight loss, safety and improvement of cardio-metabolic health risks.

A systematic review and critical assessment of health state utilities: weight change and type 2 diabetes mellitus

OBJECTIVE

The study aimed to conduct a systematic literature search to identify health state utilities for weight change in type 2 diabetes mellitus (T2DM) and to review those values for appropriateness for inclusion in a submission to the National Institute for Health and Clinical Excellence (NICE).

METHODS

The search was conducted using keywords and Medical Subject Heading (MeSH) terms designed to exhaustively capture health state utility values across a variety of known economic, health technology assessment and peer-reviewed publication databases. The values were then critically reviewed from the perspective of the NICE reference case (2008 methods guide).

RESULTS

The search resulted in a large number of repeat references across databases suggesting good sensitivity. Thirty-three articles were selected for inclusion and subjected to a critical review including their methodological quality, symmetry with the NICE reference case, sample size and country source. This critical review led to a shortlist of nine utility studies, all of which had potential for inclusion in cost-utility models or a meta-analysis.

CONCLUSIONS

A relatively large number of utilities have been collected in weight change and T2DM. Many of these utility values are not suitable for inclusion in a NICE submission. A better way of reviewing the methodological quality of utilities is needed.

A within-trial cost-effectiveness analysis of primary care referral to a commercial provider for weight loss treatment, relative to standard care--an international randomised controlled trial

Background:

Due to the high prevalence of overweight and obesity there is a need to identify cost-effective approaches for weight loss in primary care and community settings.

Objective:

We evaluated the cost effectiveness of two weight loss programmes of 1-year duration, either standard care (SC) as defined by national guidelines, or a commercial provider (Weight Watchers) (CP).

Design:

This analysis was based on a randomised controlled trial of 772 adults (87% female; age 47.4±12.9 years; body mass index 31.4±2.6 kg m⁻²) recruited by health professionals in primary care in Australia, United Kingdom and Germany. Both a health sector and societal perspective were adopted to calculate the cost per kilogram of weight loss and the ICER, expressed as the cost per quality adjusted life year (QALY).

Results:

The cost per kilogram of weight loss was USD122, 90 and 180 for the CP in Australia, the United Kingdom and Germany, respectively. For SC the cost was USD138, 151 and 133, respectively. From a health-sector perspective, the ICER for the CP relative to SC was USD18 266, 12 100 and 40 933 for Australia, the United Kingdom and Germany, respectively. Corresponding societal ICER figures were USD31 663, 24 996 and 51 571.

Conclusion:

The CP was a cost-effective approach from a health funder and societal perspective. Despite participants in the CP group attending two to three times more meetings than the SC group, the CP was still cost effective even including these added patient travel costs. This study indicates that it is cost effective for general practitioners (GPs) to refer overweight and obese patients to a CP, which may be better value than expending public funds on GP visits to manage this problem.

An economic analysis of traditional and technology-based approaches to weight loss

BACKGROUND

The financial burden and human losses associated with noncommunicable diseases necessitate cost-effective and efficacious interventions.

PURPOSE

An economic analysis of the Lifestyle Education for Activity and Nutrition (LEAN) Study; an RCT that examined the efficacy of traditional and technology-based approaches to weight loss.

METHODS

Economic analyses from an organizational perspective were conducted for four approaches: standard care control (SC); group weight-loss education (GWL); a multisensor armband (SWA); and the armband in combination with group weight-loss education (GWL+SWA). Data were collected in 2008-2009. Weight loss was the primary outcome. Total costs, costs per participant, costs per kilogram lost, and incremental cost-effectiveness ratios (ICERs) were calculated in 2010-2011. All costs are the actual expenses (i.e., staff time and materials) incurred by the LEAN study (except where noted) and reported in 2010 U.S. dollars.

RESULTS

In the sample population of 197 sedentary, overweight, and obese adults (mean [±SD] age=46.9 ± 0.8 years, BMI=33.3 ± 5.2, weight=92.8 ± 18.4 kg), the GWL+SWA was the most expensive intervention in costs/participant ($365/partic) while yielding the greatest weight loss/partic (6.59 kg). The GWL was next in cost/partic ($240), but the SWA was less expensive in cost/partic ($183) and more efficacious (3.55 vs 1.86 kg/partic). The SC did not achieve significant weight loss. The SWA was the most cost effective ($51/partic/kg lost), followed by the GWL+SWA ($55) and GWL alone ($129). The ICER suggests that for each additional kilogram lost, the GWL+SWA cost $60 more than the SWA alone.

CONCLUSIONS

The SWA was the most cost-effective intervention ($51/partic/kg lost). The addition of the GWL increased the efficacy of the SWA intervention but increased costs by $60/partic for each additional kilogram lost. The technology-based approaches were more cost effective and efficacious than traditional approaches in promoting weight loss via lifestyle changes in sedentary, overweight, and obese adults.

Economic evaluations of adult weight management interventions: a systematic literature review focusing on methods used for determining health impacts

BACKGROUND

One of the challenges when undertaking economic evaluations of weight management interventions is to adequately assess future health impacts. Clinical trials commonly measure impacts using surrogate outcomes, such as reductions in body mass index, and investigators need to decide how these can best be used to predict future health effects. Since obesity is associated with an increased risk of numerous chronic diseases occurring at different future time points, modelling is needed for predictions.

OBJECTIVE

To assess the methods used in economic evaluations to determine health impacts of weight management interventions and to investigate whether differences in methods affect the cost-effectiveness estimates.

METHODS

Eight databases were systematically searched. Included studies were categorized according to a decision analytic approach and effect measures incorporated.

RESULTS

A total of 44 articles were included; 21 evaluated behavioural interventions, 12 evaluated surgical procedures and 11 evaluated pharmacological compounds. Of the 27 papers that estimated future impacts, eleven used Markov modelling, seven used a decision tree, five used a mathematical application, two used patient-level simulation and the modelling method was unclear in two papers. The most common types of effects included were co-morbidity treatment costs, heath-related quality of life due to weight loss and gain in survival. Only 12 of the studies included heath-related quality of life gains due to reduced co-morbidities and only one study included productivity gains. Despite consensus that trial-based analysis on its own is inadequate in guiding resource allocation decisions, it was used in 39% of the studies. Several of the modelling papers used model structures not suitable for chronic diseases with changing health risks. Three studies concluded that the intervention dominated standard care; meaning that it generated more quality-adjusted life-years (QALYs) for less cost. The incremental costs per QALY gained varied from $US235 to $US56,836 in the remaining studies using this outcome measure. An implicit hypothesis of the review was that studies including long-term health effects would illustrate greater cost effectiveness compared with trial-based studies. This hypothesis is partly confirmed with three studies arriving at dominating results, as these reach their conclusion from modelling future co-morbidity treatment cost savings. However, for the remaining studies there is little indication that decision-analytic modelling disparities explain the differences.

CONCLUSIONS

This is the first literature review comparing methods used in economic evaluations of weight management interventions, and it is the first time that observed differences in study results are addressed with a view to methodological explanations. We conclude that many studies have methodological deficiencies and we urge analysts to follow recommended practices and use models capable of depicting long-term health consequences.

Cost-effectiveness of pharmacotherapy to reduce obesity

AIMS

Obesity causes a high disease burden in Australia and across the world. We aimed to analyse the cost-effectiveness of weight reduction with pharmacotherapy in Australia, and to assess its potential to reduce the disease burden due to excess body weight.

METHODS

We constructed a multi-state life-table based Markov model in Excel in which body weight influences the incidence of stroke, ischemic heart disease, hypertensive heart disease, diabetes mellitus, osteoarthritis, post-menopausal breast cancer, colon cancer, endometrial cancer and kidney cancer. We use data on effectiveness identified from PubMed searches, on mortality from Australian Bureau of Statistics, on disease costs from the Australian Institute of Health and Welfare, and on drug costs from the Department of Health and Ageing. We evaluate 1-year pharmacological interventions with sibutramine and orlistat targeting obese Australian adults free of obesity-related disease. We use a lifetime horizon for costs and health outcomes and a health sector perspective for costs. Incremental Cost-Effectiveness Ratios (ICERs) below A$50 000 per Disability Adjusted Life Year (DALY) averted are considered good value for money.

RESULTS

The ICERs are A$130 000/DALY (95% uncertainty interval [UI] 93 000-180 000) for sibutramine and A$230 000/DALY (170 000-340 000) for orlistat. The interventions reduce the body weight-related disease burden at the population level by 0.2% and 0.1%, respectively. Modest weight loss during the interventions, rapid post-intervention weight regain and low adherence limit the health benefits.

CONCLUSIONS

Treatment with sibutramine or orlistat is not cost-effective from an Australian health sector perspective and has a negligible impact on the total body weight-related disease burden.

Impact of orlistat initiation on cardiovascular treatment use: a 6-year population-based cohort study

BACKGROUND

Trials of weight-loss drugs indicate some benefits on lipids, blood glucose, or blood pressure levels. Since obesity is associated with increased cardiovascular (CV) medication use and pharmaceutical costs, weight-loss drug use could beneficially impact CV medication use.

OBJECTIVE

We examined the temporal associations between CV drugs use 3 years before and after the initiation of orlistat, a weight-loss drug.

DESIGN

An historical cohort study in the PHARMO pharmacy registry among new users of orlistat, who were in the database at least 3 years before and after such drug initiation. We assessed the prevalence of use of antihypertensive, antidiabetic, and lipid-lowering drugs within a 6-month period before and after orlistat initiation. Slopes and changes in slopes between these two periods were calculated using logistic generalized estimating equations and odds ratios (OR) with 95% confidence intervals (CI) are presented.

RESULTS

A total of 6139 subjects had a prescription of orlistat between January 1992 and May 2009. Mean ± SD age was 46.5 ± 12.5 years, with a majority of female (88.7%). Use of antihypertensive, antidiabetic, and lipid-lowering drugs increased over time, but after start of orlistat the slopes levelled-off. Initiation of orlistat resulted in a significant change in slope for antihypertensive (OR 0.79; 95% CI 0.77-0.81), antidiabetic (0.86; 0.83-0.90), and lipid-lowering drugs (0.84; 0.81-0.88).

CONCLUSIONS

Our data suggest a potential cost-effectiveness of orlistat, with a reduction in any cardiovascular comedication use over time. By potentially reducing costs of other medications use, orlistat remains as a unique option for tackling the obesity epidemic.

Altered hypothalamic function in diet-induced obesity

Energy homeostasis involves a complex network of hypothalamic and extra-hypothalamic neurons that transduce hormonal, nutrient and neuronal signals into responses that ultimately match caloric intake to energy expenditure and thereby promote stability of body fat stores. Growing evidence suggests that rather than reflecting a failure to regulate caloric intake, common forms of obesity involve fundamental changes to this homeostatic system that favor the defense of an elevated level of body adiposity. This article reviews emerging evidence that during high-fat feeding, obesity pathogenesis involves fundamental alteration of hypothalamic systems that regulate food intake and energy expenditure.

Cost-effectiveness of diet and exercise interventions to reduce overweight and obesity

OBJECTIVE

To analyze whether two dietary weight loss interventions--the dietary approaches to stop hypertension (DASH) program and a low-fat diet program--would be cost-effective in Australia, and to assess their potential to reduce the disease burden related to excess body weight.

DESIGN

We constructed a multi-state life-table-based Markov model in which the distribution of body weight influences the incidence of stroke, ischemic heart disease, hypertensive heart disease, diabetes mellitus, osteoarthritis, post-menopausal breast cancer, colon cancer, endometrial cancer and kidney cancer. The target population was the overweight and obese adult population in Australia in 2003. We used a lifetime horizon for health effects and costs, and a health sector perspective for costs. We populated the model with data identified from Medline and Cochrane searches, Australian Bureau of Statistics published catalogues, Australian Institute of Health and Welfare, and Department of Health and Ageing.

OUTCOME MEASURES

Disability adjusted life years (DALYs) averted, incremental cost-effectiveness ratios (ICERs) and proportions of disease burden avoided. ICERs under AUS$50,000 per DALY are considered cost-effective.

RESULTS

The DASH and low-fat diet programs have ICERs of AUS$12,000 per DALY (95% uncertainty range: Cost-saving- 68,000) and AUS$13,000 per DALY (Cost-saving--130,000), respectively. Neither intervention reduced the body weight-related disease burden at population level by more than 0.1%. The sensitivity analysis showed that when participants' costs for time and travel are included, the ICERs increase to AUS$75,000 per DALY for DASH and AUS$49,000 per DALY for the low-fat diet. Modest weight loss during the interventions, post-intervention weight regain and low participation limit the health benefits.

CONCLUSION

Diet and exercise interventions to reduce obesity are potentially cost-effective but have a negligible impact on the total body weight-related disease burden.

Economic evaluation of lifestyle interventions for preventing diabetes and cardiovascular diseases

Lifestyle interventions (i.e., diet and/or physical activity) are effective in delaying or preventing the onset of diabetes and cardiovascular disease. However, policymakers must know the cost-effectiveness of such interventions before implementing them at the large-scale population level. This review discusses various issues (e.g., characteristics, modeling, and long-term effectiveness) in the economic evaluation of lifestyle interventions for the primary and secondary prevention of diabetes and cardiovascular disease. The diverse nature of lifestyle interventions, i.e., type of intervention, means of provision, target groups, setting, and methodology, are the main obstacles to comparing evaluation results. However, most lifestyle interventions are among the intervention options usually regarded as cost-effective. Diabetes prevention programs, such as interventions starting with targeted or universal screening, childhood obesity prevention, and community-based interventions, have reported favorable cost-effectiveness ratios.

Clinical and economic considerations of antiobesity treatment: a review of orlistat

The objective of this study was to review the current knowledge about the use of orlistat from clinical and economic perspectives, and to assess this drug's public health impact. Weight reduction by current antiobesity drugs, compared to placebo, is at most around 5 kg. Orlistat, the most studied antiobesity drug, is associated with the least-severe adverse effects, but compared with other drugs in its class it also delivers the most modest weight loss versus placebo (less than 3 kg). Orlistat appears to have a favorable risk/benefit profile, and cost-effectiveness ratios seem to be within a range that is generally considered acceptable. In the short-term, orlistat is related to reduced diabetes incidence and to slightly improved blood pressure and lipid profiles. Long-term clinical effects have been largely unstudied, however, and this study did not find reports that considered mortality as an endpoint. Given a very low continuation with orlistat treatment in the population and very modest and, apparently, only short-term clinical effects, orlistat is not likely to have a significant impact on the population health. Public health approaches of improving environmental and social factors to foster healthier food choices and increase physical activity remain essential for addressing the obesity epidemic.

Pharmacologic therapies for obesity

This article examines the transitions in pharmacological therapy for obesity. It reviews the current options approved by the Food and Drug Administration and several drugs approved for other indications that can be used to treat obesity as well. Because weight regulation is complex and redundant systems protect against perceived starvation, optimal treatment of obesity in individual patients will likely require different combinations of behavioral, nutritional, pharmacologic, endoscopic, and surgical therapies.

Adiposopathy and bariatric surgery: is 'sick fat' a surgical disease?

OBJECTIVE

To review how bariatric surgery in obese patients may effectively treat adiposopathy (pathogenic adipose tissue or 'sick fat'), and to provide clinicians a rationale as to why bariatric surgery is a potential treatment option for overweight patients with type 2 diabetes, hypertension, and dyslipidaemia.

METHODS

A group of clinicians, researchers, and surgeons, all with a background in treating obesity and the adverse metabolic consequences of excessive body fat, reviewed the medical literature regarding the improvement in metabolic disease with bariatric surgery.

RESULTS

Bariatric surgery improves metabolic disease through multiple, likely interrelated mechanisms including: (i) initial acute fasting and diminished caloric intake inherent with many gastrointestinal surgical procedures; (ii) favourable alterations in gastrointestinal endocrine and immune responses, especially with bariatric surgeries that reroute nutrient gastrointestinal delivery such as gastric bypass procedures; and (iii) a decrease in adipose tissue mass. Regarding adipose tissue mass, during positive caloric balance, impaired adipogenesis (resulting in limitations in adipocyte number or size) and visceral adiposity are anatomic manifestations of pathogenic adipose tissue (adiposopathy). This may cause adverse adipose tissue endocrine and immune responses that lead to metabolic disease. A decrease in adipocyte size and decrease in visceral adiposity, as often occurs with bariatric surgery, may effectively improve adiposopathy, and thus effectively treat metabolic disease. It is the relationship between bariatric surgery and its effects upon pathogenic adipose tissue that is the focus of this discussion.

CONCLUSIONS

In selective obese patients with metabolic disease who are refractory to medical management, adiposopathy is a surgical disease.

A new glucagon and GLP-1 co-agonist eliminates obesity in rodents

We report the efficacy of a new peptide with agonism at the glucagon and GLP-1 receptors that has potent, sustained satiation-inducing and lipolytic effects. Selective chemical modification to glucagon resulted in a loss of specificity, with minimal change to inherent activity. The structural basis for the co-agonism appears to be a combination of local positional interactions and a change in secondary structure. Two co-agonist peptides differing from each other only in their level of glucagon receptor agonism were studied in rodent obesity models. Administration of PEGylated peptides once per week normalized adiposity and glucose tolerance in diet-induced obese mice. Reduction of body weight was achieved by a loss of body fat resulting from decreased food intake and increased energy expenditure. These preclinical studies indicate that when full GLP-1 agonism is augmented with an appropriate degree of glucagon receptor activation, body fat reduction can be substantially enhanced without any overt adverse effects.

The first decade of sibutramine and orlistat: a reappraisal of their expanding roles in the treatment of obesity and associated conditions

Ancillary therapies for weight management, consisting mainly of diet and exercise programs that incorporate variable levels of lifestyle modification techniques, are frequently ineffective to achieve clinically meaningful weight loss and maintenance. Although pharmacological treatment of obesity is widely used in most countries, the number of available drugs is still very limited. The most widely used anti-obesity agents are sibutramine and orlistat, both available in clinical practice for about a decade. A large number of clinical trials have demonstrated that both agents are safe and well tolerated, with a level of efficacy in the moderate weight loss recommended by the most relevant clinical guidelines. Several studies have assessed the efficacy and safety of sibutramine and orlistat in adolescents and also for the treatment of some associated conditions in adults, including type 2 diabetes, polycystic ovary syndrome and binge eating disorder. The positive results of these studies suggest an expanding role for both agents, not only for the treatment of obesity, but also for associated conditions. After the efficacy of orlistat for the prevention of type 2 diabetes demonstrated in the XENDOS study, the results of SCOUT study are awaited for a better evaluation of sibutramine impact on cardiovascular outcomes.