Cost-effectiveness of Bariatric Surgery in Adolescents With Obesity

Key Points

Question  Is bariatric surgery a cost-effective treatment for adolescents with severe obesity?

Findings  In this cost-effectiveness analysis, a mathematical state transition model was used to determine that bariatric surgery has an incremental cost-effectiveness ratio of $154 684 per quality-adjusted life-year (QALY) when assessed over 3 years, $114 078 per QALY over 4 years, and $91 032 per QALY over 5 years. Thus, bariatric surgery is cost-effective at 5 years using a willingness-to-pay threshold of $100 000 per QALY.

Meaning  This study underscores the need for long-term clinical trials in adolescents with at least 5 years of follow-up data that capture financial and quality-of-life end points.

Importance  Severe obesity affects 4% to 6% of US youth and is increasing in prevalence. Bariatric surgery for the treatment of adolescents with severe obesity is becoming more common, but data on cost-effectiveness are limited.

Objective  To assess the cost-effectiveness of bariatric surgery for adolescents with obesity using recently published results from the Teen-Longitudinal Assessment of Bariatric Surgery study.

Design, Setting, and Patients  A state-transition model was constructed to compare 2 strategies: no surgery and bariatric surgery. In the no surgery strategy, patients remained at their initial body mass index (calculated as weight in kilograms divided by height in meters squared) over time. In the bariatric surgery strategy, patients were subjected to risks of perioperative mortality and complications as well as initial morbidity but also experienced longer-term quality-of-life improvements associated with weight loss. Cohort demographic information—of the 228 patients included, the mean (SD) age was 17 (1.6) years, the mean (range) body mass index was 53 (34-88), and 171 (75.0%) were female—surgery-related outcomes, and base case time horizon (3 years) were based on data from the Teen-Longitudinal Assessment of Bariatric Surgery study. One-way and probabilistic sensitivity analyses were performed.

Main Outcomes and Measures  Quality-adjusted life-years (QALYs), total costs (in US dollars adjusted to 2015-year values using the Consumer Price Index), and incremental cost-effectiveness ratios (ICERs). A willingness-to-pay threshold of $100 000 per QALY was used to assess cost-effectiveness.

Results  After 3 years, surgery led to a gain of 0.199 QALYs compared with no surgery at an incremental cost of $30 747, yielding an unfavorable ICER of $154 684 per QALY. When the clinical study results were extrapolated to 4 years, the ICER decreased to $114 078 per QALY and became cost-effective by 5 years with an ICER of $91 032 per QALY. Outcomes were robust in most 1-way and probabilistic sensitivity analyses.

Conclusions and Relevance  Bariatric surgery incurs substantial initial cost and morbidity. We found that surgery could be a cost-effective treatment for adolescents with severe obesity if assessed over a time horizon of 5 years. Our study underscores the need for long-term clinical trials in adolescents with at least 5 years of follow-up data that capture financial and quality-of-life end points.

Overweight and obesity affect more than one-third of children and adolescents in the United States.¹ Severe obesity, defined as a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 35 or greater or 120% of the 95th percentile or greater (whichever is lower), affects 4% to 6% of US youth and is growing more prevalent.² Behavioral intervention is the first-line treatment for adolescents with severe obesity, but this type of intervention rarely leads to meaningful long-term weight loss in this population.² One recent study³ indicated that behavioral treatment had no effect whatsoever on adolescents with severe obesity when assessed 1, 2, and 3 years after the intervention. While other studies have found that behavioral therapy results in less than 3% total body weight loss in adolescents with obesity,^4,5 this small effect usually does not translate into meaningful change for individuals with very high baseline BMIs.

Bariatric surgery is increasingly being considered as an option for adolescents who have not achieved adequate weight loss through nonsurgical therapy. The Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study, which prospectively observed 242 adolescents undergoing weight-loss surgery, found that total body weight decreased by 27% at 3 years after surgery.⁶ In addition to enabling weight loss, surgery also helped patients avoid obesity-related comorbidities, including type 2 diabetes, renal damage, hypertension, and dyslipidemia.⁷

Bariatric surgery is performed in approximately 1000 adolescents each year, and its use in US youth is on the rise.^8,9 Nevertheless, bariatric procedures for adolescents remain highly controversial. Possible complications include anastomotic leak, sepsis, and bleeding,¹⁰ although their occurrence is rare.¹¹ In a 2007 survey, nearly half of primary care physicians indicated that they would not refer adolescents for bariatric surgery.¹² However, as surgery continues to develop a track record of efficacy and safety in the adolescent population, it has the potential to become a less controversial and more common therapeutic option. In this setting of increasing use with high initial morbidity and cost, it is important to assess the cost-effectiveness of surgical treatment to inform health care decision making. The Teen-LABS study consortium recently released 3-year results,⁶ which have enabled us to conduct a reliable cost-effectiveness analysis of bariatric surgery in adolescents.

We developed a cohort state-transition model, also known as a Markov model, using TreeAge Pro 2015 (TreeAge) to assess the cost-effectiveness of 2 strategies: no surgery and bariatric surgery (eFigure 1 in the Supplement). TreeAge Pro is a software platform that is used to build and analyze state-transition models, which are useful for assessing the effect of treatments including their cost-effectiveness. The mean (SD) age of the 228 patients from the Teen-LABS study was 17 (1.6) years, the mean (range) initial BMI was 53 (34-88), and 171 (75.0%) were female. Cohort demographic information and the time horizon (3 years) were based on data from the Teen-LABS study.⁶ After the initial analysis, the model was run beyond 3 years. The model cycle length, or time between state transitions, was 1 month. Because this was a mathematical analysis and did not include any individual-level patient data, the Massachusetts General Hospital Institutional Review Board does not require approval and informed consent in this context.

In the no surgery strategy, patients remained at their initial BMI over time.^13,14 In the bariatric surgery strategy, we based the intervention on the Teen-LABS study, where patients received either Roux-en-Y gastric bypass (161 [70.6%]) or sleeve gastrectomy (67 [29.4%]).⁶ These patients faced a small risk of 30-day mortality, based on data from the American College of Surgeons National Surgical Quality Improvement Program database (Table 1).¹⁵ We used mortality data from the National Surgical Quality Improvement Program database because no deaths occurred in the Teen-LABS study but larger data sets show nonzero mortality. Patients also faced risks of early major complications (ie, life-threatening complications or complications requiring reoperation) and minor complications (eg, readmission for dehydration), which were based on data from the Teen-LABS study.¹¹ Risks of late complications were based on data from a recent meta-analysis.¹⁶ We assumed that late complication risks were constant for the first 4 years after the operation and were halved thereafter.¹³ We estimated the background mortality according to age, sex, and BMI using data from the US Third National Health and Nutritional Examination Survey.¹⁹

The model incorporated costs of surgery and complications. Perioperative hospital costs were derived from the University HealthSystem Consortium database.¹⁸ Preoperative and postoperative intervention costs were estimated from a study that tracked costs associated with bariatric surgery in adolescents.¹⁷ Our model incorporated only costs associated with surgery and surgery-related complications; it did not include health care costs for treating obesity-related comorbidities. All costs from prior years were adjusted to 2015-year US dollars using the Consumer Price Index.²⁰

Surgical patients received an initial quality-of-life decrement associated with the operation, which was applied for 6 weeks.^13,21,22 Quality-of-life effects of complications were also incorporated; the quality-of-life decrement was applied for 4 weeks for minor complications and 6 weeks for major complications.^13,22,23 We applied a quality-of-life improvement of 0.0056 quality-adjusted life-years (QALYs) per BMI unit decrease.^24,25 Weight-loss data were based on data from the Teen-LABS study until year 3,⁶ after which weight-loss data were derived from results from the Swedish Obese Subjects study (eTables 1 and 2 in the Supplement).²⁶ Nonsurgical patients experienced no change in weight or quality of life in our analysis.^13,14

Study end points included QALYs, total costs, and incremental cost-effectiveness ratios (ICERs). A willingness-to-pay threshold of $100 000 per QALY was used to determine cost-effectiveness.²⁷ To assess the effect of model input uncertainty on cost-effectiveness results, 1-way sensitivity analyses and probabilistic sensitivity analyses were performed.

In the base case analysis, QALYs accumulated over 3 years for the no surgery and bariatric surgery strategies were 2.057 and 2.256, respectively (Table 2). The bariatric surgery strategy cost $30 747 more than the no surgery strategy over this time horizon. The ICER of bariatric surgery vs no surgery was $154 684 per QALY; using a willingness-to-pay threshold of $100 000 per QALY, bariatric surgery was not cost-effective (Figure 1). When the time horizon was extended to 4 years, the ICER of bariatric surgery vs no surgery decreased to $114 078 per QALY. Over a 5-year time horizon, this ICER further decreased to $91 032 per QALY, suggesting that bariatric surgery was cost-effective if assessed over a 5-year follow-up.

We performed 1-way sensitivity analyses over 3-, 4-, and 5-year time horizons (Figure 2; eFigures 2 and 3 in the Supplement). Bariatric surgery was never cost-effective over a 3-year time horizon; over a 4-year time horizon, bariatric surgery was cost-effective only if the cost of gastric bypass was set at its minimum value. Over a 5-year duration, bariatric surgery remained cost-effective in most sensitivity analyses. However, when the model was run using the maximum cost of gastric bypass or the maximum probability of late major complications, the ICER exceeded $100 000 per QALY and bariatric surgery was not cost-effective.

Probabilistic sensitivity was performed on the model over varied time horizons. Using a willingness-to-pay threshold of $100 000 per QALY, bariatric surgery was cost-effective with a probability of 0%, 17%, and 78% over 3, 4, and 5 years, respectively (eFigure 4 in the Supplement). Over a 6-year time horizon, bariatric surgery was cost-effective with a probability of 98%.

Our analysis demonstrates the potential value of bariatric surgery for treating adolescents with severe obesity. While bariatric surgery was not cost-effective over a 3-year time horizon—the length of follow-up currently reported in the Teen-LABS study—it could become cost-effective if assessed over a time horizon of 5 years. However, this finding was sensitive to the uncertainty surrounding the initial cost of bariatric surgery and the probability of late complications. Our results underscore the need for long-term clinical trials in adolescents with at least 5 years of follow-up data that capture financial, quality-of-life, and complication end points.

While several analyses have examined the cost-effectiveness of bariatric surgery in adults,^13,24,28-30 similar studies in children and adolescents are comparatively lacking, perhaps because of a dearth of prospective studies with more than 1 year of follow-up data.¹⁷ A strength of our analysis stems from the high-quality and relatively long-term data that we incorporated from a recently published Teen-LABS study,¹¹ which provided 3 years’ worth of comprehensive data on weight loss, complication rates, and quality of life. The Teen-LABS study also included 228 participants who underwent either laparoscopic Roux-en-Y gastric bypass (161) or laparoscopic sleeve gastrectomy (67).⁶ To our knowledge, besides our analysis, 1 other study has assessed the cost-effectiveness of bariatric surgery in adolescents,¹⁷ and it used clinical data from only 11 patients who all received gastric bypass—a procedure that is becoming less commonly used.^18,31

Other analyses focused on adults have long indicated the favorable cost-effectiveness of bariatric surgery as a treatment for obesity, including persons with mild, moderate, or severe obesity. Our analysis focused only on adolescents with severe obesity because of a lack of data supporting efficacy or safety of operation in other classes of obesity for adolescents. Several cost-effectiveness analyses have also assessed the additional benefits that bariatric surgery confers to adults with obesity-related comorbidities, such as type 2 diabetes.^24,28 Based on the 3-year results from the Teen-LABS study, bariatric surgery may lead to remission of obesity-associated comorbidities at higher rates in adolescents than in adults. In our analysis, we did not explicitly model the benefit of comorbidity improvement after bariatric surgery, such as diabetes and hypertension, which resolved in 95% and 80% of patients, respectively, in the Teen-LABS study.⁶ However, we accounted for this effect by incorporating BMI-specific mortality, which implicitly reflects the health benefits of comorbidity resolution. Additionally, our decision not to separately model each obesity-related comorbidity is conservative; even without accounting for each obesity-related condition, bariatric surgery is cost-effective over a relatively short time horizon.

Our model shows that bariatric surgery can become cost-effective over a relatively short time horizon, even without incorporating the potential cost savings that may follow bariatric surgery because of decreased health care resource use. We chose to exclude such cost savings from our model because the effect of bariatric surgery on expenditures remains an issue of significant debate, and health care costs do not appear to decrease in the 3 to 6 years immediately following bariatric surgery, even among patients with diabetes.^32-34 Our rationale is also supported by the Swedish Obese Subjects study, which found that surgically treated patients incurred more costs than nonsurgical patients in the first 6 years after the operation.³⁵

Like most modeling analyses, ours has limitations. First, we made the simplifying assumption that BMI would remain stable in nonsurgical patients. Thus, our model did not reflect the possibility of obesity severity increasing with age.³ If we modeled any potential weight gain in the nonsurgical patients, then bariatric surgery would have become cost-effective over an even shorter time horizon than we determined. Another limitation to our study is that we did not model gastric bypass and sleeve gastrectomy separately. It is likely that weight loss, comorbidity resolution, and complication risk differ according to the type of procedure. However, we believe that there are currently insufficient data to allow a meaningful cost-effectiveness comparison of these procedures in the adolescent population.

At present, bariatric surgery is performed in approximately 1000 adolescents per year. Increasing access to bariatric surgery in adolescents, even by a factor of 4, would hardly affect obesity prevalence on a population level.³⁶ For this reason, experts in childhood and adolescent obesity focus primarily on public health interventions, such as taxes on sugar-sweetened beverages, calorie labeling on restaurant menus, and nutrition standards for food in schools. From an individual-patient perspective, though, bariatric surgery can result in life-altering weight loss, which not only leads to the resolution and prevention of disease but also allows patients to avoid the stigma, bullying, and isolation that often accompany severe obesity.³⁷ As evidence supporting the safety and efficacy of bariatric surgery continues to accrue for the adolescent population, it will likely become a more accepted and commonly used therapeutic option. Our analysis indicates that it can also be cost-effective when assessed over a relatively short time horizon. Longer-term studies that track quality of life, weight loss, comorbidity resolution, and health care costs are needed to confirm our findings.

Corresponding Author: Chin Hur, MD, MPH, Institute for Technology Assessment, Massachusetts General Hospital, 101 Merrimac St, 10th Floor, Boston, MA 02114 (chur@mgh.harvard.edu).

Accepted for Publication: June 25, 2016.

Published Online: October 26, 2016. doi:10.1001/jamasurg.2016.3640

Author Contributions: Dr Hur had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All Authors.

Acquisition, analysis, or interpretation of data: Klebanoff, Chhatwal, Corey, Kaplan, Hur.

Drafting of the manuscript: Klebanoff, Nudel, Hur.

Critical revision of the manuscript for important intellectual content: All Authors.

Statistical analysis: Klebanoff, Chhatwal.

Administrative, technical, or material support: Klebanoff, Hur.

Study supervision: Corey, Hur.

Conflict of Interest Disclosures: None reported.