To compare outcomes of patients undergoing bariatric procedures in hospitals designated as centers of excellence compared with nondesignated hospitals.
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.
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 noncenters 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.
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.