Retrospective Cohort Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Endosc. Jul 16, 2017; 9(7): 296-303
Published online Jul 16, 2017. doi: 10.4253/wjge.v9.i7.296
Assessment of the July effect in post-endoscopic retrograde cholangiopancreatography pancreatitis: Nationwide Inpatient Sample
Allison R Schulman, Marwan S Abougergi, Christopher C Thompson
Allison R Schulman, Christopher C Thompson, Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, United States
Marwan S Abougergi, Catalyst Medical Consulting, LLC, Baltimore, MD 21220, United States
Author contributions: Schulman AR and Thompson CC contributed to study concept and design; Schulman AR and Abougergi MS contributed to acquisition of data, analysis and interpretation of data; Schulman AR performed statistical analysis and drafted the manuscript; Abougergi MS and Thompson CC critically revised the manuscript for important intellectual content; Thompson CC supervised the study.
Conflict-of-interest statement: All authors have no conflict of interest related to the manuscript.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at cthompson@hms.harvard.edu. Consent was not obtained as the presented data are from the National Inpatient Sample and completely anonymized without risk of identification.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Christopher C Thompson, MD, MSc, FACG, FASGE, Director of Therapeutic Endoscopy, Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, 75 Francis St., ASB II, Boston, MA 02115, United States. cthompson@hms.harvard.edu
Telephone: +1-617-5258266 Fax: +1-617-2646342
Received: December 20, 2016
Peer-review started: December 23, 2016
First decision: February 4, 2017
Revised: March 22, 2017
Accepted: June 12, 2017
Article in press: June 13, 2017
Published online: July 16, 2017
Abstract
AIM

To assess incidence of post-endoscopic retrograde cholangiopancreatography (post-ERCP) pancreatitis in the early (July/August/September) vs the late (April/May/June) academic year and evaluate in-hospital mortality, length of stay (LOS), and total hospitalization charge between these time periods.

METHODS

This was a retrospective cohort study using the 2012 Nationwide Inpatient Sample (NIS). Patients with International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9 CM) procedure codes for ERCP were included. Patients were excluded from the study if they had an ICD-9 CM code for a principal diagnosis of acute pancreatitis, if the ERCP was performed before or on the day of admission or if they were admitted to non-teaching hospitals. Post-ERCP pancreatitis was defined as an ICD-9 CM code for a secondary diagnosis of acute pancreatitis in patients who received an ERCP as delineated above. ERCPs performed during the months of July, August and September was compared to those performed in April, May and June in academic hospitals. ERCPs performed at academic hospitals during the early vs late year were compared. Primary outcome was incidence of post-ERCP pancreatitis. Secondary outcomes included in-hospital mortality, length LOS, and total hospitalization charge. Proportions were compared using fisher’s exact test and continuous variables using student t-test. Multivariable regression was performed.

RESULTS

From the 36480032 hospitalizations in 2012 in the United States, 6248 were included in the study (3065 in July/August/September and 3183 in April/May/June) in the 2012 academic year. Compared with patients admitted in July/August/September, patients admitted in April/May/June had no statistical difference in all variables including mean age, percent female, Charleston comorbidity index, race, median income, and hospital characteristics including region, bed size, and location. Incidence of post-ERCP pancreatitis in early vs late academic year were not statistically significant (OR = 1.03, 95%CI: 0.71-1.51, P = 0.415). Similarly, the adjusted odds ratio of mortality, LOS, and total hospitalization charge in early compared to late academic year were not statistically significant.

CONCLUSION

Incidence of post-ERCP pancreatitis does not differ at academic institutions depending on the time of year. Similarly, mortality, LOS, and total hospital charge do not demonstrate the existence of a temporal effect, suggesting that trainee level of experience does not impact clinical outcomes in patients undergoing ERCP.

Keywords: Pancreatitis, Academic training, Endoscopic retrograde cholangiopancreatography, Endoscopy, July effect

Core tip: The changeover of medical trainees has been shown to negatively impact patient care. At academic institutions, endoscopic retrograde cholangiopancreatography (ERCP) involves advanced endoscopy fellows, and outcomes may vary based on the time of year. We assessed the incidence of post-ERCP pancreatitis in the early vs the late academic year and evaluated in-hospital mortality, length of stay (LOS), and total hospitalization charge between these time periods. We found that the incidence of post-ERCP pancreatitis in early vs late academic year were not statistically significant. Furthermore, mortality, LOS, and total hospitalization charge in early compared to late academic year were not statistically significant.