Rectal Indomethacin Reduces Pancreatitis in High- and Low-Risk Patients Undergoing Endoscopic Retrograde Cholangiopancreatography

BACKGROUND & AIMS: Rectal indomethacin reduces the risk of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). Most studies of its efficacy included high-risk cohorts and excluded low-risk patients, including those with malignant biliary obstruction. We investigated the potential of rectal indomethacin to prevent post-ERCP pancreatitis (PEP) in a variety of patients. METHODS: We performed a retrospective cohort study of 4017 patients who underwent ERCP at the Hospital of the University of Pennsylvania, from 2009 and 2015, including 823 patients with malignant biliary obstruction. After June 2012, with a few exceptions, patients received indomethacin after their procedure. We collected data from patients' records on demographic and clinical features, procedures, and development of PEP. PEP was defined by consensus criteria. Multivariable logistic regression was used to determine adjusted odds ratios (ORs) for the association between indomethacin and PEP. RESULTS: Rectal indomethacin reduced the odds of PEP by 65% (OR, 0.35; 95% confidence interval [CI], 0.24-0.51; P<.001) and moderate-to-severe PEP by 83% (OR, 0.17; 95% CI, 0.09-0.32; P<.001). In patients with malignant obstruction, rectal indomethacin reduced the risk of PEP by 64% (OR, 0.36; 95% CI, 0.17-0.75; P<.001) and moderate-to-severe PEP by 80% (OR, 0.20; 95% CI, 0.07-0.63; P<.001). Among patients with malignant obstruction, rectal indomethacin provided the greatest benefit to patients with pancreatic adenocarcinoma: 2.31% of these patients who received rectal indomethacin developed PEP vs 7.53% who did not receive rectal indomethacin (P<.001) and 0.59% of these patients who received rectal indomethacin developed moderate-to-severe PEP vs 4.32% who did not receive rectal indomethacin (P=.001). CONCLUSIONS: In a large retrospective cohort study of patients undergoing ERCP that included low-risk patients and patients with malignant biliary obstruction, rectal indomethacin was associated with a significant decrease in the absolute rate and severity of pancreatitis.