ORIGINAL ARTICLE Primary sclerosing cholangitis increases the risk for pancreatitis after endoscopic retrograde cholangiopancreatography Erik von Seth 1,2 , Urban Arnelo 3,4 , Lars Enochsson 3,4 and Annika Bergquist 1,2 1 Department of Hepatology, Center for Digestive Diseases, Karolinska University Hospital, Stockholm, Sweden 2 Department of Medicine, Huddinge, Karolinska Institutet, Stockholm, Sweden 3 Department of Surgery, Center for Digestive Diseases, Karolinska University Hospital, Stockholm, Sweden 4 Department of Clinical Science, Intervention and Technology (CLINTEC), Division of Surgery, Karolinska Institutet, Stockholm, Sweden Keywords adverse events – ERCP – PSC Abbreviations CCA, cholangiocarcinoma; ERCP, endoscopic retrograde cholangiopancreatography; GallRiks, the swedish registry for gallstone surgery and ERCP; MRCP, magnetic resonance cholangiopancreatography; MRI, magnetic resonance imaging; OR, odds ratio; PEP, post-ERCP pancreatitis; PSC, primary sclerosing cholangitis. Correspondence Erik von Seth, K63, Department of Hepatology, Center for Digestive Diseases, Karolinska University Hospital, 14186 Stockholm, Sweden Tel: +46858582305 Fax: +46858582335 e-mail: erik.von.seth@ki.se Received 21 May 2014 Accepted 7 July 2014 DOI:10.1111/liv.12640 Abstract Background & Aims: Patients with primary sclerosing cholangitis (PSC) have an increased risk for adverse events following endoscopic retrograde cholan- giopancreatography (ERCP), mainly caused by bacterial cholangitis. The risk of pancreatitis is less examined. Therefore, our aim was to study adverse events following ERCP and to evaluate if PSC is a risk factor for pancreati- tis. Methods: Data were collected through a Swedish nationwide quality reg- istry comprising fifty-one Swedish ERCP centres. The final study cohort consisted of 8932 adults who had undergone ERCP from 1 January 2007 to 31 December 2009. A total of 141 patients had PSC. Variables of importance for adverse events were entered into a multivariate logistic regression model for risk factor analysis. Results: The following adverse events were increased in PSC as compared with non-PSC patients: overall (18.4% vs. 7.3%), pan- creatitis (7.8% vs. 3.2%, P = 0.002), cholangitis (7.1% vs. 2.1%, P < 0.001) and per-operative extravasation of contrast (5.7% vs. 0.7%, P < 0.001). PSC was shown to be an independent risk factor for all of these adverse events: pancreatitis, OR 2.02 (95% CI, 1.04–3.92), cholangitis, OR 2.88 (95% CI, 1.47–5.65), and extravasation of contrast, OR 5.84 (95% CI, 2.24– 15.23). Conclusion: The rate of adverse events overall following ERCP in PSC is 18% and PEP occurs in 8%. PSC is an independent risk factor for PEP and the risk is doubled. These findings underline the importance of a careful selection of PSC patients eligible for ERCP as well as a need for high compe- tence of the treating team. Endoscopic retrograde cholangiopancreatography (ERCP) is an essential therapeutic tool in the management of pri- mary sclerosing cholangitis (PSC). Primary sclerosing cho- langitis (PSC) patients who develop recurrent cholangitis because of dominant strictures and/or stones require urgent intervention to restore bile flow and provide relief of cholestatic symptoms. Primary sclerosing cholangitis (PSC) patients also have an increased risk of developing cholangiocarcinoma (CCA) with the incidence rate esti- mated to 1.5% per year (1), and ERCP plays a crucial role in detecting early malignancy through brush cytology and biopsies in patients with dominant strictures (2). The risk of serious adverse events following ERCP is relatively high, 4–7%, compared with other endoscopic examina- tions, but varies significantly between different studies (3). Post-ERCP pancreatitis (PEP) is the most frequent adverse event, followed by bleeding, infection and perforation. Several patient- and procedure-related risk factors for adverse events have been identified (4–7). Patients with PSC have previously been shown to have an increased risk of cholangitis following ERCP (8), while the risk of PEP is less examined. A clinical observation is that PSC patients seem to develop PEP more often than other patients undergoing ERCP and a high frequency of PEP has previously been reported (9). Disease involve- ment of the pancreatic duct in PSC is reported to be pres- ent in 24% of all PSC patients (10). We therefore hypothesize that PSC is a risk factor for PEP. The aim of this study was to determine the rate of the adverse events following ERCP in PSC patients and to evaluate if PSC is a risk factor for PEP and other adverse events following ERCP. Liver International (2014) © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 1 Liver International ISSN 1478-3223