The study by Tarride and colleagues found that the total health care expenditures decreased over time for patients undergoing Roux-en-Y gastric bypass by using a difference-in-differences approach. Costs were found to be higher in the Roux-en-Y gastric bypass cohort compared with that of the control group in the first 3 years but were similar in years 4 and 5.1
Despite the fact that the study was based on a large sample and included propensity score–matched controls, the study’s inability to account for the associated and important indirect costs (eg, costs from lost wages and absenteeism/presenteeism costs)2 and medication costs may have important consequences for the difference-in-differences results reported in this study. The findings from our recent comprehensive meta-analysis and systematic review3 suggested that there may be substantially reduced medication costs for obesity-related comorbidities even in the short term after surgery. Additionally, the review suggested that shorter-term costs inclusive of the initial procedure shift to cost savings in the longer term when indirect costs are considered.3 Therefore, we believe that studies considering indirect costs and medication costs are imperative to more thoroughly and appropriately capture the full economic effect of bariatric surgery in the short term within Canadian settings.