Importance of hospital versus surgeon volume in predicting outcomes for gastric bypass procedures.

Background: A relationship between surgical volume and improved surgical outcomes has been described in gastric bypass patients but the relative importance of surgeon versus hospital volume is unknown. Our objective was to examine whether in-hospital and 30-day mortality are determined more by surgeon volume or hospital volume or whether each has an independent effect. A retrospective cohort study was performed of all hospitals in Pennsylvania providing gastric bypass surgery from 1999 to 2003.

Methods: Data from the Pennsylvania Health Care Cost Containment Council included 14,714 gastric bypass procedures in patients aged >18 years. In-hospital and 30-day mortality were stratified by hospital volume categories (high [≥300], medium [125-299], and low [<125]) and surgeon volume categories (high [≥50] and low [<50]). Multivariate analyses were performed using logistic regression analysis to control for patient demographics and severity.

Results: High-volume surgeons at high-volume hospitals had the lowest in-hospital mortality rates of all categories (.12%) and low-volume surgeons at low-volume hospitals had the poorest outcomes (.57%). The same trend was observed for 30-day mortality (.30% versus .98%). After controlling for other covariates, high-volume surgeons at high-volume hospitals also had significantly lower odds of both in-hospital (odds ratio 20, P = .002) and 30-day mortality (odds ratio .30, P = .001). This relationship held true even after excluding surgeons who only performed procedures within a single year.

Conclusion: In Pennsylvania, both higher surgeon and hospital volume were associated with better outcomes for bariatric surgical procedures. Although a high-surgeon volume correlated with lowered mortality, we also found that high-volume hospitals demonstrated improved outcomes, highlighting the importance of factors other than surgical expertise in determining the outcomes.