Comparison of Investigations Following Inpatient and Outpatient Endoscopic Retrograde Cholangiopancreatography and Their Impact on Complication Rates and Length of Hospital Stay: A Retrospective Cohort Study.

Introduction Endoscopic retrograde cholangiopancreatography (ERCP) is a therapeutic procedure for conditions affecting the biliary and pancreatic ductal systems. Complications include post-ERCP pancreatitis (PEP), cholangitis, and bleeding, which typically present within the first few hours post-procedure. This study aimed to determine if investigations following ERCP were indicated with respect to the European Society of Gastroenterology and Endoscopy (ESGE) guidelines and if there was variation in practice for inpatients versus outpatients. Methods Data were collected retrospectively from the endoscopy software Endobase (Olympus Corporation, Hamburg, Germany) for all patients who underwent an inpatient and outpatient ERCP over a six-month period between November 2022 and April 2023 at a district general hospital in Northwest England. Subsequent data post ERCP were collected from electronic patient records (EPR), including length of stay, reason for overnight admission, readmission within seven days, and mortality within seven days. Data were analysed using JASP 0.95.2 (JASP team, University of Amsterdam, Amsterdam, Netherlands (jasp-stats.org)) and compared against the ESGE guidelines as recommendations of best practice.  Results During the six-month period, 134 patients underwent an ERCP, of which 69% (n=92) were inpatients and 31% (n=42) were outpatients. Out of the 92 inpatients, only 3.3% were discharged the same day compared to 95.2% of day cases ERCPs (p < 0.0001). In the inpatient cohort, 51% (n=45) were admitted for asymptomatic routine investigations (blood or observation) with no indication as per ESGE guidelines. None of the 45 patients admitted were diagnosed with an ERCP-related complication. This resulted in 63 additional bed days and 50 additional episodes of venepuncture. Out of the day case cohort (n=42), no patients were admitted for asymptomatic routine investigations. There was no significant difference in the overall complication rates (p=0.339) between day case and inpatient ERCP.  Conclusion Our study supports current ESGE guidance that routine investigations following ERCP are not necessary in asymptomatic patients with no risk factors for complications. Over half of patients (51%) admitted following an inpatient ERCP could have been safely discharged the same day following a six-hour observation period without the need for further investigation.