Table 1 Primary endpoint: definitions of biliary events

Biliary pancreatitis

Diagnosis of acute pancreatitis if at least two of the three following features are present [19]:

1. Upper abdominal pain;

2. Serum lipase or amylase levels above three times the upper level of normal;

3. Characteristic findings of acute pancreatitis on cross-sectional abdominal imaging.

Biliary pancreatitis if one of the following definitions is present [20]:

1. Gallstones and/or sludge diagnosed on imaging (transabdominal or endoscopic ultrasound or computed tomography);

2. In the absence of gallstones and/or sludge, a dilated common bile duct on ultrasound (>8 mm in patients ≤75 years old or >10 mm in patients >75 years old);

3. The following laboratory abnormality: alanine aminotransferase (ALAT) level >2 times higher than normal values, with ALAT >aspartate aminotransferase.

Acute cholecystitis

Defined according to the 2007 Tokyo classification, grade I to III [21, 22].

A. Local signs of inflammation:

1) Murphy’s sign;

2) RUQ mass/pain/tenderness.

B. Systemic signs of inflammation:

1) Fever;

2) Elevated C-reactive protein;

3) Elevated white blood cell count.

C. Imaging findings characteristic of acute cholecystitis

Definite diagnosis

1) One item in A and one item in B are positive;

2) C confirms the diagnosis when acute cholecystitis is suspected clinically.

Biliary colic

Upper abdominal pain (either right upper quadrant or epigastric pain) lasting at least 30 minutes, according to the Rome criteria [22].