Bariatric Surgery Outcomes at Designated Centers of Excellence vs Nondesignated Programs

Objective: To compare outcomes of patients undergoing bariatric procedures in hospitals designated as centers of excellence compared with nondesignated hospitals. Design: The 2005 National Inpatient Survey was used to compare outcomes at designated vs nondesignated hospitals. In addition to conventional null-hypothesis statistical testing to assess differences, effect sizes were calculated to estimate the clinical significance for observed differences. Results: Centers of excellence performed substantially more operations than nondesignated centers. Despite this, outcomes were equivalent at centers of excellence and hospitals without this designation. Volume-outcome modeling attempting to identify the optimal number for a minimum volume threshold for bariatric operations revealed that annual procedure volume has a weak effect on outcomes. Similarly, many variables that were statistically significantly different between centers and non-centers proved to be clinically unimportant by effect size analysis. Risk adjustment was effectively achieved by using the Agency for Healthcare Research and Quality-supplied variables all-payer severity-adjusted diagnostic related group expected charges and deaths. Conclusions: Designation as a bariatric surgery center of excellence does not ensure better outcomes. Neither does high annual procedure volume. Extra expenses associated with center of excellence designation may not be warranted.