Introduction: Perforation during ERCP is rare (< 1%) but potentially fatal event (up to 20% mortality). Given its rarity, most data is through study of case series from large centers or analysis of large databases. Although a meta-analysis has shown fewer adverse events as a composite (bleeding, pancreatitis, perforation) during ERCP performed at high volume centers, there is very little real-world data on endoscopist and center procedural volumes, ERCP duration, and complexity on the occurrence of perforation. Methods: Patients from Clinical Outcome Research Initiative National Endoscopic Database CORI-NED (2000-2012) who underwent ERCP were stratified based on the endoscopist’s volume (quartiles), center’s volume (quartiles), total procedure duration and complexity grade of the ERCP based on procedure details. Effects of these variables on the perforations that occurred were studied. Continuous variables were compared between perforations (P) and no perforations (NP) using the unpaired t-test with statistical significance set at p< 0.05 (2-tailed). Results: A total of 14,153 ERCPs were performed by 258 endoscopists with 20 reported perforations (0.14%) among 16 endoscopists. Mean patient age in years (±SD) 61.6± 14.8 vs 58.1±18.8 (P vs NP, p=NS, Figure a). Cannulation rate was 100% and 91.5% for P and NP respectively. 13/20 (65%) of endoscopists were high volume performers in the 4th quartile and 11/20 (55%) of perforations occurred in centers with the highest volumes (4th quartile). Total procedure duration in minutes was 40.33 ± 23.5 vs 60.1± 29.9 (P vs NP, p=0.008, highly significant, Figure b). Fluoroscopy duration in minutes was 3.3 ± 2.3 vs 3.3± 2.6 (P vs NP p=NS, Fig 1c). 50% of the procedures were complex and greater than grade 1 difficulty (Table). 3/20 (15%) patients had prior biliary surgery. 13/20 (65%) had sphincterotomies performed with stent insertion. Peritonitis occurred in only 1/20 (0.5%), (Table). Conclusion: Overall adverse events as a composite during ERCP are known to occur at a lower rate with higher volume endoscopists and centers. However, perforations studied from the national database have shown prolonged and more complex procedures performed by high volume endoscopists at high volume centers contributing to perforations. This is likely a result of high-risk procedures undertaken in patients with complex pathology at tertiary and quaternary centers.Figure 1.: (a) Age (years) box plot comparing no perforation group versus perforation group (b) Total ERCP duration (minutes) box plot comparing no perforation group versus perforation group 1. Fluoroscopy duration (minutes) box plot comparing no perforation group versus perforation group Table 1. - Endoscopist & center volume quartiles, indications & complexity of ERCP procedures that resulted in perforations Physician Physician volume quartile Center volume quartile Indication ERCP difficulty grade Dilation of strictures Sphincterotomy performed Stent placement Sphincterotomy Device Peritonitis Prior biliary Surgery 1 4 4 LHD tumor biopsy 3 No No No NA No No 2 4 4 Pancreatic tumor 3 No Yes Yes * No Yes 2 4 4 CBD stone 3 Yes Yes Yes Cotton Cannulotome No No 2 4 4 CBD stricture 3 Yes Yes Yes Cotton Cannulotome No No 3 3 3 RHD tumor biopsy 3 No Yes Yes Cotton Cannulotome No No 4 3 2 CBD stone 1 No Yes Yes Cotton Cannulotome No No 5 4 4 CBD stone 1 No Yes Yes Papillotome Yes No 6 4 3 Stent placement 1 No Yes Yes Autotome No No 7 4 3 CBD stone 1 No No No * No No 8 3 4 CBD stone 1 No No No * No No 9 4 3 Pancreatic tumor 3 No Yes Yes Cotton Cannulotome No No 10 3 3 Sphincter of Oddi dysfunction 3 No Yes Yes * No No 11 4 4 CBD stone 2 No Yes Yes Cannulating Sphincterotome No Yes 11 4 4 Stent replacement 1 No No No NA No No 11 4 4 Pancreatic pseudocyst drainage 4 No Yes Yes Needle Knife Precut No Yes 12 4 4 CBD stone 1 No Yes Yes * No No 13 4 4 CBD stone 1 No No No NA No No 14 3 3 Stent placement 1 No Yes Yes Cotton Cannulotome No No 15 3 3 CBD stone 1 No No No NA No No 16 3 3 CBD stone 3 No No No NA No Yes *unavailable.