Association of Roux-en-Y Gastric Bypass With Postoperative Health Care Use and Expenditures in Canada.

Importance: Results of previous studies are mixed regarding the economic implications of a Roux-en-Y gastric bypass (RYGB). Objective: To assess the 5-year incremental health care use and expenditures after RYGB. Design, Setting, and Participants: This population-based cohort study conducted in Ontario, Canada, used a difference-in-differences approach to compare health care use and expenditures between patients who underwent a publicly funded RYGB from March 1, 2010, to March 31, 2013, and propensity score-matched control individuals who did not undergo a surgical bariatric procedure. The study period allowed for a minimum 60 months of follow-up because, at that time, the most recent date for which administrative data on health care and expenditures were available was March 31, 2018. Data sources included the Ontario Bariatric Registry linked to several Ontario health administrative databases and the Electronic Medical Record Administrative Data Linked Database. Health care use and expenditures data for 5 years before and 5 years after the index date (procedure date for RYGB group; random date for controls) were analyzed. Data analyses were performed March 12, 2019, to March 10, 2020. Intervention: RYGB procedure. Main Outcomes and Measures: The primary outcome was total health care expenditures. Results: The final propensity score-matched cohorts comprised 1587 individuals in the RYGB group (mean [SD] age, 47 [10.2] years) and 1587 controls (mean [SD] age, 47 [12.2] years); each group had 1228 women (77.4%) and a mean body mass index (calculated as weight in kilograms divided by height in meters squared) of 46. Mean total health care expenditures (2017 Canadian dollars) per patient in the RYGB group increased from CAD $15 594 (95% CI, CAD $14 743 to CAD $16 614) (US $12 008 [95% CI, US $11 353 to US $12 794]) in the 5 years before the procedure to CAD $30 389 (95% CI, CAD $28 789 to CAD $32 232) (US $23 401 [95% CI, US $22 169 to US $24 821]) over the 5 years after the procedure, a difference of CAD $14 795 (95% CI, CAD $13 172 to CAD $16 480) (US $11 393 [95% CI, US $10 143 to US $12 691]). For the control group, mean total health care expenditures per individual increased from CAD $16 109 (95% CI, CAD $14 727 to CAD $17 591) (US $12 405 [95% CI, US $11 341 to US $13 546]) 5 years before the index date to CAD $20 073 (95% CI, CAD $18 147 to CAD $22 169) (US $15 457 [95% CI, US $13 974 to US $17 071]) 5 years after the date, a difference of CAD $3964 (95% CI, CAD $2250 to CAD $5875) (US $3053 [95% CI, US $1733 to US $4524]). Overall, the difference-in-differences estimate of the net cost of RYGB was CAD $10 831 (95% CI, CAD $8252 to CAD $13 283) (US $8341 [95% CI, $6355 to $10 229]) over the 5-year period. This amount excluded the mean (SD) cost associated with the index date: CAD $6501 (CAD $1087) (US $5006 [US $837]) for the RYGB cohort and CAD $9 (CAD $72) (US $7 [US $55]) for the controls. The cost differential was primarily associated with increased hospitalizations in the first months immediately after RYGB. Expenditures leveled off in year 3 after the index date; differences in total expenditures between the RYGB and control cohorts were not statistically significantly different in years 4 and 5. Conclusions and Relevance: Health care expenditures in the 3 years after publicly funded RYGB were higher in patients who underwent the procedure than in control individuals, but the costs were similar thereafter. This finding suggests the need to decrease hospital and emergency department readmissions after surgical bariatric procedures because such use is associated with increased spending.