Roux-en-Y gastric bypass (RYGB) may be the most cost-effective weight reduction strategy in patients with severe obesity and type 2 diabetes (T2D) at 5 years compared with medical therapy and sleeve gastrectomy (SG), according to study results published in JAMA Network Open.

Researchers sought to estimate the direct medical costs, quality-adjusted survival, and cost-effectiveness of medical therapy, SG, and RYGB to treat US adults with severe obesity and T2D for 5 years.

For the study, researchers created a microsimulation model that estimated T2D remission, BMI changes, survival, complications from surgery, direct medical costs, and QOL with medical therapy, SG, and RYGB. Using 1999 to 2018 data from the National Health and Nutrition Examination Survey (NHANES), researchers were able to simulate nationally representative cohorts of US adults aged 18 years and older with body mass index (BMI) of at least 40 and T2D.

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The primary endpoints were mean direct medical costs in 2020 US dollars, mean quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) from a health care sector perspective. Future costs and QALYs were discounted annually by 3%.

Overall, the model simulated 1000 cohorts of 10,000 patients. Of the total patient population,16% had mild T2D, 56% had moderate T2D, and 28% had severe T2D at baseline. The simulated patients had a mean age of 54.6 years (95% CI, 54.2-55.0 years), 61.6% (95% CI, 60.1%-63.4%) were women, and 65.1% (95% CI, 63.6%- 66.7%) were non-Hispanic White.

At 3 months postsurgery, the projected proportion of T2D remission was highest in participants who had RYGB and mild T2D at baseline (92.9%; 95% CI, 86.4%-97.6%) and lowest in those who had SG and severe diabetes at baseline (5.7%; 95% CI, 1.0%-13.9%).

SG was projected to increase QALYs by a mean of 0.31 QALY (95% CI, 0.13-0.66 QALY), compared with medical therapy. RYGB had the largest increase in QALYs overall (mean, 0.44 QALY; 95% CI, 0.21-0.86 QALY) and when stratified according to baseline T2D severity: mild (mean, 0.59 QALY; 95% CI, 0.35-0.98 QALY), moderate (mean, 0.50 QALY; 95% CI, 0.25-0.88 QALY), and severe (mean, 0.30 QALY; 95% CI, 0.07-0.79 QALY).

RYGB was cost-effective vs medical therapy (ICER of $46,877 per QALY gained) among all participants, with an 83.0% probability of being the preferred strategy. SG was not less favorable to RYGB only in patients with mild T2D. RYGB was the most cost-effective strategy in patients with mild T2D at baseline (ICER vs SG $36,479 per QALY gained; 73.7% probability preferred), less cost-effective for those who had moderate T2D at baseline (ICER, $37,056 per QALY; 85.6% probability preferred), and least cost-effective in participants who had severe T2D at baseline (ICER vs medical therapy, $98,940 per QALY gained; 40.2% probability preferred).

Among several study limitations, the investigators did not assess all types of bariatric surgery as comparators and focused only on the most common approaches. Also, they assumed that patients with gastroesophageal reflux disease were not included, but some model parameters may have been derived from populations that included patients with the disorder.

“Despite its higher upfront surgical costs, RYGB was estimated to be the most cost-effective treatment over 5 years and became even more cost-effective over longer time horizons (eg, 10 and 30 years),” the researchers wrote.

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Lauren BN, Lim F, Krikhely A, et al. Estimated cost-effectiveness of medical therapy, sleeve gastrectomy, and gastric bypass in patients with severe obesity and type 2 diabetes. JAMA Netw Open. Published online February 14, 2022. doi:10.1001/jamanetworkopen.2021.48317