Purpose We aimed to estimate the total cost of bariatric surgery in Denmark.

Materials and Methods The study population included all Danish citizens >= 18 years who had received bariatric surgery, identified in the Danish National Patient Register in the period from 2002 to 2018. Patients who had received bariatric surgery were matched with three controls on gender, year of birth, and region of residence. A difference-in-difference approach was used to estimate the healthcare costs attributable to bariatric surgery from 3 years before to 5 years after surgery.

Results Total healthcare costs for cases receiving bariatric surgery during the first 5 years following surgery amounted to EUR 32,899, and EUR 16,651 for their matched controls. Thereby, the difference in total healthcare costs (EUR 16,248) between persons receiving bariatric surgery and their matched controls was 2.2 times the DRG rate for the surgery itself (EUR 7387).

Moreover, the results suggest that receiving bariatric surgery led to a total increase in gross earnings of EUR 5970 (5%) and a total reduction in receipt of transfer payments of EUR 4488 (12%) in the period up until 5 years after surgery.

Conclusion The results showed a significant and persistent increase in healthcare costs for people with obesity receiving bariatric surgery during the first 5 years after surgery. We also found that bariatric surgery was associated with increased attachment to the labor market.