The purpose of this study is to compare the incidence of post-ERCP pancreatitis (PEP) in chronic pancreatitis (CP) patients to that in biliary disease patients, to determine whether CP patients in early clinical stage have a higher PEP incidence, and to identify the predictive and protective factors for PEP in chronic pancreatitis patients.

Analysis of patients with chronic pancreatitis (CP group) and biliary disease (BD group) in Changhai Hospital from January 2011 to May 2015 were conducted. Difference of PEP incidences between BD group and CP group, as well as between M-ANNHEIM subcategories were calculated by chi-square test or Fisher's exact test. The predictive and protective factors for PEP were investigated by univariate and multivariate analysis.

Inclusion Criteria:

• patients with an endoscope inserted to cannulate the pancreatic/biliary duct were included.

Exclusion Criteria:

• patients in whom the papilla of Vater was not reached;
• patients who underwent stent removal procedures without ductal cannulation;
• patients in whom the intubation was failed.

Chronic pancreatitis patients underwent ERCP from January 2011 to May 2015 in Changhai Hospital.