Background Obesity has become major public health problem around the world. Lifestyle interventions, Pharmacotherapy and bariatric surgery are the common intervention to reduce weight in clinical practice. This study aims to conduct an economic evaluation of Duodenal-Jejunal Bypass Sleeve (DJBS) plus Intensive Lifestyle Intervention (ILI) compared with ILI only in people with obesity in China. Methods A hybrid model using a Decision Tree and Markov model was used to compare 9-month and lifetime horizon cost-effectiveness between DJBS plus ILI and ILI only. The data on clinical effectiveness were based on a prospective, open-label, and randomized trial (NCT05938231). This study employed 1-3 times the Gross Domestic Product (GDP) per capita (¥85,498, exchange rate: $1 US dollar = ¥6.73, 2022) and disposable income per capita (¥36,883, 2022) as the Willingness-To-Pay (WTP) thresholds. One-way, probabilistic sensitivity and scenario analysis were performed to test the robustness of the results. Results The results of the 9-month decision tree model showed that compared to ILI only, DJBS plus ILI decreased body mass index (BMI) by 1.69 kg/m2 (1.41 vs. 3.10), with an increasing cost of ¥28,963.98 yuan (¥29,111.06 vs.¥147.08). The incremental cost-effectiveness ratio (ICER) was ¥17,138.45 per unit decrease of BMI. The lifetime horizon model showed that compared to ILI only, DJBS plus ILI had a higher cost of ¥13261.94 yuan (¥31,688.98 vs. ¥18,427.04), while with a life-year increase of 0.02 (9.43 vs. 9.41) and quality-adjusted life years (QALYs) increase of 0.15 (7.82 vs. 7.67) per people with obesity. The ICER was ¥88,412.93 per QALY gained. Probability sensitivity analysis showed the robustness of the economic evaluation results. Conclusion The findings suggested that DJBS plus ILI was not a cost-effective strategy over a lifetime horizon when the WTP threshold was set at GDP per capita and disposable income per capita. However, it was considered cost- effective when the threshold was set at 1.03 times GDP per capita.
