Health Expenditures Decline After Bariatric Surgery for Patients With Type 2 Diabetes

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.

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 nonsurgical patients, we compared total, outpatient, inpatient, and medication expenditures 3 years presurgery and 5.5 years postsurgery, using generalized estimating equations. Expenditures were estimated in 6-month intervals.

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

Patients with type 2 diabetes undergoing bariatric surgery have significantly lower total postsurgical expenditures than matched control patients, primarily because of substantial reductions in pharmacy expenditures. The long-term cost savings associated with bariatric surgery are likely to increase further, given the rapidly escalating costs of diabetes pharmacotherapy.