Volume, specialty background, practice pattern, and outcomes in endoscopic retrograde cholangiopancreatography: an analysis of the national inpatient sample

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is a complex endoscopic procedure performed by both gastroenterologists and surgeons. There has been recent controversy regarding training paradigms for gastrointestinal endoscopy. No prior studies have evaluated comparative outcomes for ERCP in relation to specialty training background. This study utilized the National Inpatient Sample (NIS) to assess ERCP outcomes as a function of training background, practice pattern, and individual provider volume. Methods: NIS data was queried from 2007 to 2009. Gastroenterologists and surgeons were identified by procedural profiles and unique physician identifiers. Comorbidity was assessed via Charlson Score. Outcomes including cost, length of stay (LOS), and mortality were analyzed, with and without propensity score matching (PSM). Analysis of outcomes as a function of provider procedural volume was also performed. Comparison for statistical significance was accomplished via t test. Results: A total of 110,811 ERCP’s were identified, of which 42,025 (37.9%) were performed by surgeons. Surgeons exhibited longer LOS (8.7 vs. 7.2 days), overall cost ($24,739 vs. $16,960), and mortality (3.9 vs. 1.2%, odds ratio 3.3), with p < 0.001 for all measures. 71.6% of surgical patients, versus 19.6% of gastroenterologic, underwent subsequent inpatient laparoscopic cholecystectomy or laparotomy. Outcome differences persisted when PSM included performance of subsequent laparoscopic cholecystectomy. Evaluation of minimum performance standards revealed up to a fivefold increased mortality for providers who performed less than 5 ERCP’s/year, irrespective of specialty background. Conclusions: Gastroenterologists demonstrate favorable gross outcomes compared to surgeons performing ERCP. Differences may correlate in part with more frequent subsequent surgical management of comorbid conditions by surgical providers. Lower volume providers achieve inferior outcomes regardless of specialty background. Analyses of this type may help inform discussions on optimal training and proficiency paradigms, including maintenance of proficiency, for therapeutic endoscopic procedures.