Surgeon Volume Impacts Hospital Mortality for Pancreatic Resection

Abstract

Improved outcomes after pancreatic resection (PR) by high volume (HV) surgeons have been reported in single center studies, which may be confounded with potential selection and referral bias. We attempted to determine if improved outcomes by HV surgeons are reproducible when patient demographic factors are controlled at the population level. Using the Nationwide Inpatient Sample, discharge records with surgeon identifiers for all nontrauma PR (n = 3581) were examined from 1998 to 2005. Surgeons were divided into 2 groups: (HV; > or = 5 operations/year) or low volume (LV; <5 operations/year). We created a logistic regression model to examine the relationship between surgeon type and operative mortality while accounting for patient and hospital factors. To further eliminate differences in cohorts and determine the true effect of surgeon volume on mortality, case-control groups based on patient demographics were created using propensity scores. One hundred thirty-four HV and 1450 LV surgeons performed 3581 PR in 742 hospitals across 12 states that reported surgeon identifier information over the 8-year period. Patients who underwent PR by HV surgeons were more likely to be male, white raced, and a resident of a high-income zip code (P < 0.05). Significant independent factors for in-hospital mortality after PR included increasing age, male gender, Medicaid insurance, and surgery by HV surgeon. HV surgeons had a lower adjusted mortality compared with LV surgeons (2.4% vs. 6.4%; P < 0.0001). After controlling for patient demographics and factors, pancreatic resection by a HV surgeon in this case-controlled cohort was independently associated with a 51% reduction in in-hospital mortality.