Risk Factors for Common Bile Duct Stones in Patients with Previous Cholecystectomy: A Multicenter Prospective Proof-of-Concept Study.

Objectives: Most studies assess risk factors for common bile duct (CBD) stones in patients with gallbladder in situ. We aimed to assess risk factors for CBD stones in patients with previous cholecystectomy in a proof-of-concept study. Methods: We enrolled consecutive patients undergoing EUS for suspected symptomatic CBD stones and recorded demographic variables, clinical presentation, liver function tests (LFTs), and transabdominal ultrasound (US) findings. EUS was used as gold standard for CBD stones. Multivariate analysis was used to identify risk factors in the training set; a model was created and tested on the validation set. Results: A total of 211 patients (25.6% male; median age, 66 [49-75] years old) were enrolled; 77.7% presented with abdominal pain, 30.3% with hyperbilirubinemia, 26.5% with pancreatitis, and 61.1% with LFT alterations. Ultrasound showed CBD dilation in 37.4% patients. Overall, 96 (45.5%) patients had CBD stones. According to multivariate analysis, male gender (OR 2.54 [1.26-5.09]; p = 0.009), age > 63 years (OR 3.06 [1.63-5.72]; p < 0.001), LFT alteration (OR 2.62 [1.40-4.91]; p = 0.003), and CBD dilation (OR 2.46 [1.31-4.65]; p = 0.005) were independently related to CBD stones. A model was created based on the number of risk factors on admission; patients with no risk factor had a 9.5% prevalence of CBD stones; those with one risk factor, 26.7%; two risk factors, 53.2%; three risk factors, 66.7%; and four risk factors, 100%. Conclusions: The results of this proof-of-concept study identify male gender, age, LFT alteration, and CBD dilation as risk factors for CBD stones in patients with previous cholecystectomy. An adequate assessment of the pre-test probability will guide patients' subsequent management.