Surgeon and hospital volume outcomes in bariatric surgery: a population-level study.

Background: Outcomes after bariatric surgery are tied to surgical volume; however, this relationship is not clearly established for each procedure.

Objectives: To evaluate the impact of surgeon/hospital volumes on morbidity after bariatric surgery and identify volume cutoffs.

Setting: Multi-centric population-level study, province of Quebec, Canada.

Methods: We studied a population-based cohort of all morbidly obese patients who underwent bariatric surgery in Quebec, Canada during 2006 to 2012. We evaluated only the most common procedures in North America, Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). Multilevel, cross-classified logistic regressions were used to test the effects of annual surgeon volume (SV) and hospital volume (HV) on a composite 90-day postoperative outcome. Receiver operator curve was used to identify volume thresholds.

Results: Overall, 821 patients had RYGB and 1802 underwent SG by 34 surgeons in 15 centers. For RYGB, 10-case increase in SV was associated with adjusted odds ratio of .82 (95% confidence interval: .71-.94). Similar increase in HV resulted in odds ratio of .86 (95% confidence interval: .77-.96). Annual SV threshold of 21 RYGBs and HV of 25 cases were identified (area under the curve = .60 and .61, respectively). For SV, being in the higher volume category translated into an absolute risk reduction of 12.5% for 90-day major morbidity. For SG, annual 10-case increase in SV and HV was not significantly associated with a decrease in 90-day postoperative morbidity.

Conclusion: SV and HV are significant independent predictors of 90-day major morbidity after RYGB. This study further supports establishing minimum surgical volume requirements for more complex anastomotic procedures like RYGB. However, the role of volume targets in SG remains unclear.