Lee 2009

Methods	Single centre, RCT. Enrolment period: June 2006 to May 2007. Endoscopist(s): all procedures were performed by a single experienced endoscopists.
Participants	Country: Korea. 300 consecutive patients with native papilla and pancreaticobiliary disease who were candidates for therapeutic biliary ERCP.
Interventions	1. Guidewire‐assisted cannulation: a hydrophilic tipped 0.035 inch guidewire (Jagwire, Boston Scientific) through a sphincterotome (Olympus). The tip of the sphincterotome was inserted into the papilla, followed by advancement of the guidewire and opacification. Guidewire was advanced by an assistant. 2. Contrast‐assisted cannulation: standard method of cannulation through a sphincterotome (Olympus).
Outcomes	PEP; successful cannulation of the CBD; hyperamylasaemia; inadvertent PD cannulation / injection; use of needle‐knife sphincterotomy; risk factors for PEP; procedure‐related complications (bleeding, perforation); mortality.
Notes	1. Defined PEP according to the consensus definition (Cotton 1991). 2. Graded the severity of PEP based on the consensus criteria (Cotton 1991). 3. Did not report on the use of technique 'cross‐over'. 4. Precut was permitted. A fistulotomy with a needle‐knife as rescue management was performed when access to the CBD failed despite five attempts of pancreatic cannulation or 10 minutes of biliary cannulation in both groups. 5. PD stents were not used for prevention of PEP. 6. Did not report on the PEP rate in patients who had precut. Authors contacted: 0% (0/28) in the guidewire‐assisted group vs. 19.4% (7/36) in the contrast‐assisted group who underwent precut developed PEP.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization "by means of computer‐generated numbers".
Allocation concealment (selection bias)	Unclear risk	No information was provided.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No information was provided. Endoscopists could not be blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information was provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No patient was lost to follow‐up. PEP data reported in ITT sample. "The serum amylase level was measured before ERCP and 24 hours thereafter". It is unclear whether patients were discharged home or admitted for observation.
Selective reporting (reporting bias)	Low risk	Reported all planned outcomes.
Other bias	Low risk	No other risk of bias