Association of Post-ERCP Complications with Hospital Admission Period

Abstract

Introduction: Numerous studies have been performed to evaluate the hypothesis that patient outcomes are worse during the beginning of the academic year for trainees in July. However, no study has assessed for differences in Endoscopic Retrograde Cholangiopancreatography [ERCP] outcomes based on admission quarter. We studied differences in post-ERCP complication rates of gastrointestinal [GI] bleed, perforation, cholecystitis and mortality based on which quarter of the year the patient was admitted. We hypothesized that complications following ERCPs would be greatest in the third quarter, corresponding to the beginning of the academic year for trainees. Methods: We used the National Inpatient Sample databases from the years 2008 to 2012 to identify patients that underwent ERCP using the International Classification of Diseases, Ninth Edition, Clinical Modification codes. Data points that did not contain the admission month were excluded from the study. January, February, and March were re-coded as first quarter. April, May, and June were re-coded as second quarter. July, August, and September were re-coded as third quarter. Finally, October, November, and December were re-coded as fourth quarter. Patients who experienced GI bleed, perforation, cholecystitis or mortality following ERCP were then identified. ANOVA analysis was performed in STATA to calculate differences in complication rates between quarters of the year. Results: 274,807 ERCP cases were included in our study population which represented a 20% sample of the United States. Cholecystitis rates were highest in the third quarter, 0.35%, versus 0.32%, 0.31%, and 0.32% in the first, second, and fourth quarters, respectively (p-value 0.118). Mortality rates and infection rates were highest in the fourth quarter, (1.49% p-value<0.001; 10.77% p-value<0.001, respectively), when compared to the rest of the year. No difference was seen in rates of GI bleed and perforation. Patients admitted in the third quarter were older (59.6 years old, p-value<0.001), had a longer length of stay (6.6 days, p-value 0.003), and had a higher Elixhauser Comorbidity Score (2.2, p-value<0.001) when compared to the rest of the year. Conclusion: Although post-ERCP cholecystitis rates were highest in the third quarter, other complications, including mortality, did not have any association with the start of the academic year for new trainees. Interestingly, patients admitted in the third quarter were older and had a higher Elixhauser Comorbidity Score.2835_A Figure 1. Multivariable regression model of post-ERCP GI bleed, perforation, cholecystitis and mortality rates based on admission quarter2835_B Figure 2. Comparison of complication rates by admission quarter using one-way ANOVA