Downloaded from http://journals.lww.com/pancreasjournal by BhDMf5ePHKbH4TTImqenVEyMrwFXE1ZV9rk8HXK3VO0exLIkkAF+ra8afp2gigVn on 10/21/2018 Cannabis Use Is Associated With Increased Risk of Post–Endoscopic Retrograde Cholangiopancreatography Pancreatitis Analysis of the US Nationwide Inpatient Sample Database, 2004–2014 Basile Njei, MD, MPH,* Prabin Sharma, MD,† Thomas R. McCarty, MD,† Manpreet Singh, MD,† Lamia Haque, MD, MPH,† Harry R. Aslanian, MD,* Priya Jamidar, MD,* and Thiruvengadam Muniraj, MD, PhD* Objective: The aim of this study was to investigate the impact of cannabis on post–endoscopic retrograde cholangiopancreatography pancreatitis (PEP). Methods: The US Nationwide Inpatient Sample was queried to identify patients who underwent endoscopic retrograde cholangiopancreatography pancreatitis from 2004 to 2014. Cannabis use was identified by Interna- tional Classification of Diseases, Ninth Edition codes, and patients in re- mission were excluded. Poisson regression models were used to derive adjusted incidence risk ratios (IRRs) for outcomes. Results: Among 37,712 patients with PEP, 0.4% had documented cannabis use disorder. From 2004 to 2014, the rate of PEP and cannabis use increased (8.9%–11.0% [P < 0.01] and 0.20%–0.70% [P < 0.01], respectively). Univariate analysis demonstrated cannabis was associated with increased risk of PEP (IRR, 1.70; 95% confidence interval [CI], 1.50–1.90; P < 0.01). On multivariate analysis, cannabis use was an independent predictor of PEP (IRR, 1.2; 95% CI, 1.1–1.4; P = 0.004). Cannabis was not associated with in-hospital death (IRR, 0.15; 95% CI, 0.02–1.04; P = 0.06) but was associ- ated with shorter hospital stay (IRR, 0.96; 95% CI, 0.94–0.98; P < 0.001) and lower costs (IRR, 0.91; 95% CI, 0.91–0.92; P < 0.001). Conclusions: Cannabis use was associated with an increase in PEP with- out significant increase in mortality. Key Words: cannabis use disorder, endocannabinoids, endoscopic retrograde cholangiopancreatography (ERCP), pancreatic sphincterotomy, post-ERCP pancreatitis (PEP) (Pancreas 2018;47: 1142–1149) E ndoscopic retrograde cholangiopancreatography (ERCP) is a widely accepted endoscopic procedure, which has revolution- ized the diagnosis and management of pancreatobiliary disease. 1 Although elevation of amylase levels is common postprocedure, some patients may develop more serious complications, the most common of which is post-ERCP pancreatitis (PEP). 1,2 Current liter- ature estimates the incidence of PEP to be approximately 3% to 10%; however, PEP rates may be as high as 15% or more in high-risk patients. 3 Cannabis or marijuana has high rates of consumption world- wide, with approximately 183 million people having used cannabis globally. 4 Data also suggest that an increasing number of people re- quire treatment for cannabis use highlighting that the substance may have more adverse events than previously estimated. 4,5 Cannabis- related adverse events have traditionally involved cognitive im- pairments and psychiatric disturbances; however, consumption of synthetic cannabinoids may have more severe adverse events. 6 Studies in mice with cerulein-induced pancreatitis have shown that administration of anandamide, a cannabinoid receptor agonist to mice, increases the severity of pancreatitis. 7 The first case of presumed cannabis-induced pancreatitis in humans was reported in 2004 by Grant and Gandhi 8 with several subsequent cases that followed. 9–13 With this limited evidence, cannabis appears to have a dose-related effect on acute pancreatitis; however, no available literature exists to investigate the role of cannabis use and the development of PEP. 14 The purpose of this study was to evaluate the impact of can- nabis use on PEP and hospital resources in patients after ERCP. Herein, we hypothesized that cannabis use would be associated with an increased incidence of PEP. MATERIALS AND METHODS Data Source The study sample originated from the US National Inpatient Sample (NIS) database, which includes hospitalized patients in the United States during the 2004 to 2014 period. This registry is part of the Healthcare Cost and Utilization Project, sponsored by the Agency for Healthcare Research and Quality. 15 Each dis- charge is coded with a principal diagnosis for that specific hospi- talization in addition to the potential for 14 secondary diagnoses and 15 associated procedures. Detailed information regarding the NIS database is highlighted in Supplemental Digital Content, Appendix 1 (http://links.lww.com/MPA/A675). Study Groups and Inclusion Criteria Using the NIS data set, all patients 18 years or older were in- cluded if they had a primary or secondary procedure code for ERCP. Endoscopic retrograde cholangiopancreatography proce- dures were identified using the International Classification of Dis- eases, Ninth Edition, Clinical Modification (ICD-9-CM) codes. From the *Section of Digestive Diseases and †Department of Internal Medicine, Yale University School of Medicine, New Haven, CT. Received for publication March 14, 2018; accepted July 15, 2018. Address correspondence to: Basile Njei, MD, MPH, Section of Digestive Disease Yale University School of Medicine, 333 Cedar St, New Haven, CT 06520 (e‐mail: basile.njei@yale.edu). The authors declare no conflict of interest. Because the US National Inpatient Sample is publicly available and includes deidentified information, the Yale University School of Medicine Review Board deemed this study exempt from full review. All authors approved of the final version of the manuscript. B.N. and P.S. are co-first authors. Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.pancreasjournal.com). Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/MPA.0000000000001143 ORIGINAL ARTICLE 1142 www.pancreasjournal.com Pancreas • Volume 47, Number 9, October 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.