Cost-effectiveness of metabolic surgery for the treatment of type 2 diabetes and obesity: a systematic review of economic evaluations

Randomized Controlled Trial Based US Commercial Payor Cost-Effectiveness Analysis of Endoscopic Sleeve Gastroplasty Versus Lifestyle Modification Alone for Adults With Class I/II Obesity

PURPOSE

Endoscopic sleeve gastroplasty (ESG) is a minimally invasive day procedure that the MERIT randomized controlled trial (RCT) has demonstrated to be an effective and safe method of weight loss versus lifestyle modification alone. We sought to evaluate the cost-effectiveness of ESG from the perspective of a US commercial payer in a cohort of adults with class II and class I obesity with diabetes based on this RCT.

MATERIALS

We used a Markov modelling approach with BMI group health states and an absorbing death state. Baseline characteristics, utilities, BMI group transition probabilities, and adverse events (AEs) were informed by patient-level data from the MERIT RCT. Mortality was estimated by applying BMI-specific hazard ratios to US general population mortality rates. We used BMI-based health state utilities to reflect the impact of obesity comorbidities and applied disutilities due to ESG AEs. Costs included intervention costs, AE costs, and BMI-based annual direct healthcare costs to account for costs associated with obesity comorbidities. A willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY) was assumed.

RESULTS

In our base-case analysis over a 5-year time horizon, ESG was cost-effective versus lifestyle modification alone with an incremental cost-effectiveness ratio of $23,432/QALY. ESG remained cost-effective in all sensitivity analyses we conducted and was dominant in analyses with longer time horizons.

CONCLUSION

ESG is a cost-effective treatment option for people living with obesity and should be considered in commercial health plans as an additional treatment option for clinically eligible patients.

Application of a transparent artificial intelligence algorithm for US adults in the obese category of weight

OBJECTIVE AND AIMS

Identification of associations between the obese category of weight in the general US population will continue to advance our understanding of the condition and allow clinicians, providers, communities, families, and individuals make more informed decisions. This study aims to improve the prediction of the obese category of weight and investigate its relationships with factors, ultimately contributing to healthier lifestyle choices and timely management of obesity.

METHODS

Questionnaires that included demographic, dietary, exercise and health information from the US National Health and Nutrition Examination Survey (NHANES 2017-2020) were utilized with BMI 30 or higher defined as obesity. A machine learning model, XGBoost predicted the obese category of weight and Shapely Additive Explanations (SHAP) visualized the various covariates and their feature importance. Model statistics including Area under the receiver operator curve (AUROC), sensitivity, specificity, positive predictive value, negative predictive value and feature properties such as gain, cover, and frequency were measured. SHAP explanations were created for transparent and interpretable analysis.

RESULTS

There were 6,146 adults (age > 18) that were included in the study with average age 58.39 (SD = 12.94) and 3122 (51%) females. The machine learning model had an Area under the receiver operator curve of 0.8295. The top four covariates include waist circumference (gain = 0.185), GGT (gain = 0.101), platelet count (gain = 0.059), AST (gain = 0.057), weight (gain = 0.049), HDL cholesterol (gain = 0.032), and ferritin (gain = 0.034).

CONCLUSION

In conclusion, the utilization of machine learning models proves to be highly effective in accurately predicting the obese category of weight. By considering various factors such as demographic information, laboratory results, physical examination findings, and lifestyle factors, these models successfully identify crucial risk factors associated with the obese category of weight.

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.

Randomized Trial of Effect of Bariatric Surgery on Blood Pressure After 5 Years

BACKGROUND

Obesity represents a major obstacle for controlling hypertension, the leading risk factor for cardiovascular mortality.

OBJECTIVES

The purpose of this study was to determine the long-term effects of bariatric surgery on hypertension control and remission.

METHODS

We conducted a randomized clinical trial with subjects with obesity grade 1 or 2 plus hypertension using at least 2 medications. We excluded subjects with previous cardiovascular events and poorly controlled type 2 diabetes. Subjects were assigned to Roux-en-Y gastric bypass (RYGB) combined with medical therapy (MT) or MT alone. We reassessed the original primary outcome (reduction of at least 30% of the total antihypertensive medications while maintaining blood pressure levels <140/90 mm Hg) at 5 years. The main analysis followed the intention-to-treat principle.

RESULTS

A total of 100 subjects were included (76% women, age 43.8 ± 9.2 years, body mass index: 36.9 ± 2.7 kg/m2). At 5 years, body mass index was 36.40 kg/m2 (95% CI: 35.28-37.52 kg/m2) for MT and 28.01 kg/m2 (95% CI: 26.95-29.08 kg/m2) for RYGB (P < 0.001). Compared with MT, RYGB promoted a significantly higher rate of number of medications reduction (80.7% vs 13.7%; relative risk: 5.91; 95% CI: 2.58-13.52; P < 0.001) and the mean number of antihypertensive medications was 2.97 (95% CI: 2.33-3.60) for MT and 0.80 (95% CI: 0.51-1.09) for RYGB (P < 0.001). The rates of hypertension remission were 2.4% vs 46.9% (relative risk: 19.66; 95% CI: 2.74-141.09; P < 0.001). Sensitivity analysis considering only completed cases revealed consistent results. Interestingly, the rate of apparent resistant hypertension was lower after RYGB (0% vs 15.2%).

CONCLUSIONS

Bariatric surgery represents an effective and durable strategy to control hypertension and related polypharmacy in subjects with obesity. (GAstric bypass to Treat obEse Patients With steAdy hYpertension [GATEWAY]; NCT01784848).

Addressing uncertainty about the role of structured lifestyle modification for metabolic surgery patients

There is good evidence that structured lifestyle modification programmes improve health in patients with metabolic and cardiovascular disorders, but there is no specific evidence that they improve outcomes in patients undergoing metabolic or obesity surgery. Despite expert consensus guidelines stating this fact, some healthcare systems still compel patients to participate in a structured lifestyle modification programme prior to metabolic or obesity surgery. There is a well-established need for individualised multidisciplinary dietetic and physical activity care for metabolic and obesity surgery patients, and the benefits of intentional weight loss prior to surgery are well proven, but these are distinct from potentially harmful requirements for patients to undertake compulsory structured lifestyle programmes of fixed duration, frequency and intensity, which may delay surgery and reinforce obesity stigma. A critical step in rejuvenating metabolic surgery is to reframe patient participation in structured lifestyle modification programmes as an opportunity for education and empowerment, not as an indicator of motivation or suitability for metabolic surgery. Large, well-designed and adequately powered clinical trials are needed to address uncertainties in the evidence base for these programmes. Given genuine equipoise, they will need to determine whether "surgery plus lifestyle" is superior to "surgery plus placebo". Moreover, they will need to determine the cost-effectiveness of these programmes and identify some of the factors giving rise to the substantial heterogeneity in responses to structured lifestyle modification.

Cost-Effectiveness of Bariatric Surgery in Patients Living with Obesity and Type 2 Diabetes

Aims

The favourable effects of bariatric surgeries on body weight reduction and glucose control have been demonstrated in several studies. Additionally, the cost-effectiveness of bariatric surgeries has been confirmed in several analyses. The aim of the current analysis was to demonstrate the cost-effectiveness of bariatric surgeries in obese patients with type 2 diabetes in Hungary compared to conventional diabetes treatments based on economic modelling of published clinical trial results.

Materials and Methods

Patients entered the simulation model at the age of 45 with body mass index (BMI) ≥ 30 kg/m2 and type 2 diabetes. The model was performed from the public payer's perspective, comparing sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) procedures to conventional care of diabetes. The results were provided separately for three BMI categories.

Results

The base-case analysis demonstrated that both surgery types were dominant; i.e., they saved 17 064 to 24 384 Euro public payer expenditures and resulted in improved health outcomes (1.36 to 1.50 quality-adjusted life years gain (QALY)) in the three BMI categories. Bariatric surgeries extended the life expectancy and the disease-free survival times of all the investigated diabetes complications. All the scenario analyses confirmed the robustness of the base-case analysis, such that bariatric surgeries remained dominant compared to conventional diabetes treatments.

Conclusion

The results of this cost-effectiveness analysis highlight the importance of bariatric surgeries as alternatives to conventional diabetes treatments in the obese population. Therefore, it is strongly recommended that a wider population has access to these surgeries in Hungary.

UK cost-effectiveness analysis of endoscopic sleeve gastroplasty versus lifestyle modification alone for adults with class II obesity

BACKGROUND

Endoscopic sleeve gastroplasty (ESG) is a minimally invasive procedure that has been demonstrated in the MERIT randomised, controlled trial to result in substantial and durable additional weight loss in adults with obesity compared with lifestyle modification (LM) alone. We sought to conduct the first cost-effectiveness analysis of ESG versus LM alone in adults with class II obesity (BMI 35.0-39.9 kg/m2) from a national healthcare system perspective in England based on results from this study.

METHODS

A 6-state Markov model was developed comprising 5 BMI-based health states and an absorbing death state. Baseline characteristics, utilities, and transition probabilities were informed by patient-level data from the subset of patients with class II obesity in MERIT. Adverse events (AEs) were based on the MERIT safety population. Mortality was estimated by applying BMI-specific hazard ratios from the published literature to UK general population mortality rates. Utilities for the healthy weight and overweight health states were informed from the literature; disutility associated with increasing BMI in the class I-III obesity health states was estimated using MERIT utility data. Disutility due to AEs and the prevalence of obesity-related comorbidities were based on the literature. Costs included intervention costs, AE costs, and comorbidity costs.

RESULTS

ESG resulted in higher overall costs than LM alone but led to an increase in quality-adjusted life years (QALYs). The incremental cost-effectiveness ratio (ICER) for ESG vs LM alone was £2453/QALY gained. ESG was consistently cost effective across a wide range of sensitivity analyses, with no ICER estimate exceeding £10,000/QALY gained. In probabilistic sensitivity analysis, the mean ICER was £2502/QALY gained and ESG remained cost effective in 98.25% of iterations at a willingness-to-pay threshold of £20,000/QALY.

CONCLUSION

Our study indicates that ESG is highly cost effective versus LM alone for the treatment of adults with class II obesity in England.

Bariatric-metabolic surgery for NHS patients with type 2 diabetes in the United Kingdom National Bariatric Surgery Registry

AIM

Bariatric-metabolic surgery is approved by the National Institute of Health and Care Excellence (NICE) for people with severe obesity and type 2 diabetes (T2DM) (including class 1 obesity after 2014). This study analysed baseline characteristics, disease severity and operations undertaken in people with obesity and T2DM undergoing bariatric-metabolic surgery in the UK National Health Service (NHS) compared to those without T2DM.

METHODS

Baseline characteristics, trends over time and operations undertaken were analysed for people undergoing primary bariatric-metabolic surgery in the NHS using the National Bariatric Surgical Registry (NBSR) for 11 years from 2009 to 2019. Clinical practice before and after the publication of the NICE guidance (2014) was examined. Multivariate logistic regression was used to determine associations with T2DM status and the procedure undertaken.

RESULTS

14,948/51,715 (28.9%) participants had T2DM, with 10,626 (71.1%) on oral hypoglycaemics, 4322 (28.9%) on insulin/other injectables, and with T2DM diagnosed 10+ years before surgery in 3876 (25.9%). Participants with T2DM, compared to those without T2DM, were associated with older age (p < 0.001), male sex (p < 0.001), poorer functional status (p < 0.001), dyslipidaemia (OR: 3.58 (CI: 3.39-3.79); p < 0.001), hypertension (OR: 2.32 (2.19-2.45); p < 0.001) and liver disease (OR: 1.73 (1.58-1.90); p < 0.001), but no difference in body mass index was noted. Fewer people receiving bariatric-metabolic surgery after 2015 had T2DM (p < 0.001), although a very small percentage increase of those with class I obesity and T2DM was noted. Gastric bypass was the commonest operation overall. T2DM status was associated with selection for gastric bypass compared to sleeve gastrectomy (p < 0.001).

CONCLUSION

NHS bariatric-metabolic surgery is used for people with T2DM much later in the disease process when it is less effective. National guidance on bariatric-metabolic surgery and data from multiple RCTs have had little impact on clinical practice.