Health Expenditures of Patients With Diabetes After Bariatric Surgery: Comparing Gastric Bypass and Sleeve Gastrectomy.

Background: Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) differ in their effects on body weight and risk for reoperation. However, it is unclear whether long-term health expenditures differ by procedure type in patients with diabetes.

Objective: To compare health expenditures 3 years before and 5.5 years after bariatric surgery between patients with diabetes undergoing RYGB versus SG.

Design: Retrospective cohort study using target trial emulation principles.

Setting: Integrated health system.

Patients: Patients with diabetes undergoing RYGB ( = 3147) or SG ( = 3510) from 2012 to 2019.

Measurements: Total, inpatient, outpatient, and medication expenditures.

Results: Characteristics of patients undergoing RYGB and SG were well balanced after weighting; 73% were female, average body mass index was 43.8 kg/m, and average age was 50 years. Expenditures per 6-month period decreased by about 30% for both groups, from $4039.06 (95% CI, $3770.88 to $4326.31) 3 years before to $2441.13 (CI, $2151.07 to $2770.30) 5.5 years after RYGB and from $3918.37 (CI, $3658.75 to $4196.40) 3 years before to $2658.15 (CI, $2279.17 to $3100.16) 5.5 years after SG. Total expenditures after surgery did not differ between groups through 5.5 years (difference at 5.5 years, -$217.02 [CI, -$671.29 to $201.96]) except for the first 6 months, when expenditures were transiently higher in the RYGB group (difference, $564.32 [CI, $232.60 to $895.20]), driven by a higher inpatient admission rate. Otherwise, postsurgical outpatient and medication expenditures did not appear to differ between RYGB and SG.

Limitation: Unobserved confounding.

Conclusion: Overall expenditures decreased substantially in the postsurgical period, primarily due to reductions in pharmacy expenditures, with no differences between RYGB and SG except in the first 6 months after surgery.

Primary Funding Source: National Institute of Diabetes and Digestive and Kidney Diseases.