Why the incidence of post-ERCP pancreatitis varies considerably? Factors affecting the diagnosis and the incidence of this complication.

The reported incidence of post-ERCP/sphincterotomy pancreatitis ranges between 1.3 and 24.4% in non-selected series. This varying incidence likely reflects on the one hand difference in patient populations, indications and endoscopic expertise and, on the other hand, different definitions of pancreatitis and methods of data collection. Among a number of patient-related factors recognized at risk for post-ERCP pancreatitis in four recent large prospective studies, the combination of female gender, normal serum bilirubin levels and recurrent abdominal pain suggesting sphincter of Oddi dysfunction and previous post-ERCP pancreatitis placed patients at an increasingly higher risk of pancreatitis. Among the technique-related risk factors for post-ERCP pancreatitis, biliary sphincter balloon dilation, difficult cannulation, sphincter of Oddi manometry and pancreatic sphincterotomy have also been recognized as significant risk factors. However, since the case mix in non-selected series does not significantly differ in the different studies, it is logical to assume that the different criteria adopted for defining the post-ERCP pancreatitis play a key role in the reported wide variation of incidence reported for this complication. The occurrence and duration of pain and the amplitude of serum amylase after ERCP are critical points in the definition of post-ERCP pancreatitis. Although a consensus conference identified 24-hour persisting pain associated with hyperamylasemia greater than 3 times the upper reference limit as an indicator of pancreatitis, these two parameters are however considered in a different manner in the studies available up to now. In a prospective study where we calculated the incidence of post-ERCP pancreatitis by using the most widely used criteria, for both occurrence and duration of pancreatic pain and serum amylase amplitude, the incidence of post-procedure pancreatitis ranged from 1.9 to 11.7% depending on the criteria adopted.