What is the most adapted indication of prophylactic pancreatic duct stent within the high-risk group of post-endoscopic retrograde cholangiopancreatography pancreatitis? Using the propensity score analysis

Background Conducting randomized controlled trial (RCT) for each of the risk factors associated with prophylactic pancreatic duct stent (PPDS) for post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is difficult owing to the volume of cases and ethical considerations. In this study, we tried to reveal the degree of preventive effects of PPDS for each individual risk factor within the high-risk group of PEP using the propensity score analysis. Methods The clinical data of 1131 ERCP practices performed at Kobe University Hospital from April 2006 to February 2009 were collected prospectively. We investigated their clinical characteristics including the risk factors of PEP, the use of PPDS and complications of ERCP. We conducted the stratification analysis using the propensity score matching analysis. Results In 210 propensity score-matched ERCPs, PPDS proved to be effective in preventing PEP in patients with a history of pancreatitis (odds ratio 0.11, 95% CI 0.01-0.76, P = 0.01) and cases of difficult cannulation (requiring more than 30 min) (odds ratio 0.13, 95% CI 0.01-1.14, P = 0.08). Conclusions Patients with a history of pancreatitis and cases of difficult cannulation are strongly recommended for PPDS placement. The propensity score analysis can be adapted to the ERCP-related analysis with many procedure-related factors with using retrospective data, and may be adapted to investigate the matters that are unsuitable for RCT by volume and ethical issue.