Might be over-evaluated: Predicting choledocholithiasis in patients with acute biliary pancreatitis

The increase in liver cholestasis enzyme and bilirubin levels, especially due to pancreatitis, mimics choledocholithiasis. This study aimed to examine the relationship between demographic and laboratory cut-off values and the presence of choledocholithiasis in patients with acute biliary pancreatitis (ABP).

Patients diagnosed with ABP in the Department of General Surgery at Istanbul Faculty of Medicine between January 2010 and December 2022 were retrospectively analyzed. The presence of stones in the common bile duct was determined based on the results of magnetic resonance cholangiopancreatography (MRCP), endoscopic ultrasound (EUS), and endoscopic retrograde cholangiopancreatography (ERCP). Demographic and laboratory values of patients with and without bile duct stones were compared. Cut-off values were determined using receiver operating characteristic (ROC) curve analysis, and logistic regression analysis and modeling was performed for each variable.

A total of 1,026 ABP patients were evaluated. Patients whose enzyme levels were not elevated and those who did not undergo MRCP were excluded. A total of 584 patients were included in the study, and choledocholithiasis was detected in 188 (32.2%) patients. In multivariate analysis, age, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and direct bilirubin (DB) were found to be statistically associated with choledocholithiasis. The cut-off values were determined as 65 years for age, 394 U/L for GGT, 173 U/L for ALP, and 1.42 mg/dL for direct bilirubin. In the group where all four parameters were below these cut-off values, suggesting a clean common bile duct, it was observed that the negative predictive value was 97%.

Based on the demographic and laboratory data of patients with ABP, we were able to predict with more than 97% accuracy that the common bile duct was clean. Considering that our study only included patients who underwent MRCP due to elevated enzyme levels and suspicion of choledocholithiasis, the negative predictive value would be even higher if patients with acute biliary pancreatitis with normal enzyme levels were included. Additionally, no complications were observed in any of the patients during follow-up. This finding suggests that patients whose common bile duct is predicted to be clean can initially be monitored and supported with additional imaging methods if necessary. As a result, unnecessary imaging can be avoided, reducing costs and preventing the mortality and morbidity associated with unnecessary procedures.