Which Volume Matters More? A Systematic Review and Meta-Analysis of Hospital vs Surgeon Volume in Intra-Abdominal Emergency Surgery

Background: Understanding the impact of hospital and surgeon volume on emergency intra-abdominal surgery procedures and determining which measure is more influential in improving outcomes can guide regionalization of care. This systematic review, meta-analysis, and meta-regression synthesizes evidence regarding the impact of hospital and surgeon volume on mortality. Methods: A literature search without language restriction was performed in the PubMed, Web of Science, and Cochrane databases. Cohort studies assessing the impact of hospital/surgeon volume on mortality after intra-abdominal emergency procedures with data collected after the year 2000 were included and analyzed using a random effects model. A sub-group analysis assessing impact of hospital volume on high and low complexity procedures and ruptured aortic artery aneurysm (RAAA) repair was performed. Another sub-group analysis comparing high-volume surgeons in a low-volume hospital and low-volume surgeons in a high-volume hospital was also performed. PROSPERO: CRD42022358879 Results: The search yielded 2153 articles, of which 33 cohort studies were included and determined to be good quality using the Newcastle Ottawa Scale. In 22 studies with available data for the meta-analysis, mortality was significantly higher in the low hospital volume and low surgeon volume cohort. The sub-group analysis found significantly higher mortality only in high complexity procedures and RAAA repair. Mortality was significantly lower in the cohort with high-volume surgeons at low-volume hospitals. Conclusion: High hospital volume was associated with lower mortality in all except low-complexity intra-abdominal emergency procedures. High surgeon volume was associated with lower mortality and there is limited evidence of it being the most protective.