Volume and outcome relationship in bariatric surgery in the laparoscopic era

Abstract

The relationship between volume and outcomes in bariatric surgery is well established in the literature. However, the analyses were performed primarily in the open surgery era and in the absence of national accreditation. The recent Metabolic Bariatric Surgery Accreditation and Quality Improvement Program proposed an annual threshold volume of 50 stapling cases. This study aimed to examine the effect of volume and accreditation on surgical outcomes for bariatric surgery in this laparoscopic era. The Nationwide Inpatient Sample was used for analysis of the outcomes experienced by morbidly obese patients who underwent an elective laparoscopic stapling bariatric surgical procedure between 2006 and 2010. In this analysis, low-volume centers (LVC < 50 stapling cases/year) were compared with high-volume centers (HVC ≥ 50 stapling cases/year). Multivariate analysis was performed to examine risk-adjusted serious morbidity and in-hospital mortality between the LVCs and HVCs. Additionally, within the HVC group, risk-adjusted outcomes of accredited versus nonaccredited centers were examined. Between 2006 and 2010, 277,760 laparoscopic stapling bariatric procedures were performed, with 85% of the cases managed at HVCs. The mean number of laparoscopic stapling cases managed per year was 17 ± 14 at LVCs and 144 ± 117 at HVCs. The in-hospital mortality was higher at LVCs (0.17%) than at HVCs (0.07%). Multivariate analysis showed that laparoscopic stapling procedures performed at LVCs had higher rates of mortality than those performed at HVCs [odds ratio (OR) 2.5; 95% confidence interval (CI) 1.3-4.8; p < 0.01] as well as higher rates of serious morbidity (OR 1.2; 95% CI 1.1-1.4; p < 0.01). The in-hospital mortality rate at nonaccredited HVCs was 0.22% compared with 0.06% at accredited HVCs. Multivariate analysis showed that nonaccredited centers had higher rates of mortality than accredited centers (OR 3.6; 95% CI 1.5-8.3; p < 0.01) but lower rates of serious morbidity (OR 0.8; 95% CI 0.7-0.9; p < 0.01). In this era of laparoscopy, hospitals managing more than 50 laparoscopic stapling cases per year have improved outcomes. However, nonaccredited HVCs have outcomes similar to those of LVCs. Therefore, the impact of accreditation on outcomes may be greater than that of volume.