Multicenter retrospective cohort study: Using trends in liver function tests to predict spontaneous passage of common bile duct stones in choledocholithiasis

Aim: Endoscopic retrograde cholangiopancreatography (ERCP) is the modality of choice in patients who are diagnosed with choledocholithiasis, but it carries potentially life-threatening risks and is not readily available in rural hospitals. Due to the lack of access to this service, trend of liver function tests is often used to predict the spontaneous passage of common bile duct (CBD) stone to prevent performing a negative ERCP. The aim of this study is to investigate whether the trend of liver function tests can be used to predict passage of common bile duct stone in patients who have radiological evidence of choledocholithiasis. Methods: The liver function tests (LFTs) of patients diagnosed with choledocholithiasis at two separate hospitals in New Zealand and Australia were collected at two points retrospectively. The change in LFT values between diagnosis and immediately prior to ERCP was analyzed. Results: Total of 409 patients were selected with 108 (26%) and 301 (74%) patients from Australia and New Zealand, respectively. Demographic and LFT values were statistically different between the two centers, but the female sex was significantly predominant in both. Cumulative data showed that 37% of patients diagnosed with choledocholithiasis had no stone during the ERCP procedure. Increased age was statistically significant in patients with a persistent stone on ERCP. Importantly, there was no statistical difference between LFT values of patients with persistent gallstones shown on ERCP compared to those who have passed their gallstones spontaneously. Aspartate aminotransferase (AST) was significantly associated with a persistent gallstone (p = 0.041), but its clinical value is questionable. Conclusion: Decreasing trend in LFTs and their individual components are poor predictors of persistent gallstones in patients diagnosed with choledocholithiasis. Two-thirds of these patients have persistent stones and ERCP remains an important diagnostic and therapeutic modality for patients at significant risk of disease complications.