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

Abstract

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.

Figure 1.. Trends for Hospitalizations and Emergency Department (ED) Visits

Vertical line with 0 indicates the index date, with the numbers on its right marking the period after the index date and the (negative) numbers on its left marking the period before the index date. Mean numbers of hospitalizations (A) and ED visits (B) were based on a total number of 1587 individuals before the index date (time 0) for both Roux-en-Y gastric bypass (RYGB) and control groups. For the RYGB group, the numbers of patients were 1587 for year 1, 1579 for year 2, 1571 for year 3, 1564 for year 4, and 1552 for year 5, with 1541 having 60 months of data. For the control group, the numbers of individuals were 1587 for year 1, 1584 for year 2, 1575 for year 3, 1566 for year 4, and 1556 for year 5, with 1531 having 60 months of data.

Figure 2.. Trends for Specialist Visits and Total Health Care Expenditures

Vertical line with 0 indicates the index date, with the numbers on its right marking the period after the index date and the (negative) numbers on its left marking the period before the index date. Mean numbers of specialist visits (A) and total health care expenditures (B) were based on a total number of 1587 individuals before the index date (time 0) for both Roux-en-Y gastric bypass (RYGB) and control groups. For the RYGB group, the numbers of patients were 1587 for year 1, 1579 for year 2, 1571 for year 3, 1564 for year 4, and 1552 for year 5, with 1541 having 60 months of data. For the control group, the numbers of individuals were 1587 for year 1, 1584 for year 2, 1575 for year 3, 1566 for year 4, and 1556 for year 5, with 1531 having 60 months of data.

Figure 3.. Total Health Care Expenditures for Matched Patients With Roux-en-Y Gastric Bypass (RYGB) and Control Individuals per Year of Analysis

The whiskers indicate the mean health care expenditures and CIs at each period for both RYGB and control groups. For year 1, mean (SD) numbers do not include the costs associated with the index date, which were CAD $6501 (CAD $1087) (US $5006 [US $837]) for the patients who underwent RYGB and CAD $9 (CAD $72) (US $7 [US $55]) for the control individuals. Data were based on 1587 individuals before the index date (time 0) for both groups. For the RYGB group, the numbers of patients were 1587 for year 1, 1579 for year 2, 1571 for year 3, 1564 for year 4, and 1552 for year 5, with 1541 having 60 months of data. For the control group, the numbers of individuals were 1587 for year 1, 1584 for year 2, 1575 for year 3, 1566 for year 4, and 1556 for year 5, with 1531 having 60 months of data. To convert mean health care expenditures from 2017 Canadian dollars to 2017 US dollars, divide by 1.2986.