Health Expenditures Decline after Bariatric Surgery for Patients with Type 2 Diabetes

Objective: Bariatric surgery lowers the risk of developing microvascular and macrovascular complications of type 2 diabetes, but it is unclear whether it also lowers long-term health expenditures in this population.

Research Design and Methods: In a retrospective cohort study of 6,690 patients with obesity and type 2 diabetes who underwent bariatric surgery in 2012-2019 and 19,122 matched non-surgical patients, we compared total, outpatient, inpatient, and medication expenditures 3 years pre- and 5.5 years post-surgery, using generalized estimating equations. Expenditures were estimated in 6-month intervals.

Results: Surgical and non-surgical cohorts were well-matched, with 73% female, average body mass index 44 kg/m2, mean age 50 years, and 32% on insulin. Estimated total expenditures were similar between surgical and non-surgical patients up to 1 year pre-surgery. Total expenditures were significantly lower for surgical patients starting 1-year post-surgery and up to 5.5 years post-surgery compared to controls ($566 lower per 6-month interval at 5.5 years; 95% confidence interval -$807, -$316). Expenditure differences were largely attributable to a 56% drop in medication expenditures for surgical patients, from $2,204 in the 6 months pre-surgery to $969/6-month interval at 5.5 years post-surgery. Surgical patients had a higher probability of inpatient admission throughout the post-surgical period (4.0-6.5% versus 2.4-3.1% per 6-month interval).

Conclusions: Patients with type 2 diabetes undergoing bariatric surgery have significantly lower total post-surgical expenditures than matched controls, due primarily to substantial reductions in pharmacy expenditures. The long-term cost savings associated with bariatric surgery are likely to increase further given rapidly escalating costs of diabetes pharmacotherapy.