A validated score predicting common bile duct stone in patients hospitalized with acute calculus cholecystitis: a multi-center retrospective study

Background: Concomitant common bile duct (CBD) stone in the setting of acute calculous cholecystitis (ACC) should be suspected once abnormal liver indices are noticed. Aim: We aimed to identify predictors of CBD stone in patients hospitalized with ACC. Methods: We performed a retrospective multi-center, case-controlled, study from 1st of January 2016 until the 31th of December 2018. Inclusion criteria included patients with an established diagnosis of ACC based on clinical, laboratory and radiological criteria and who had an endoscopic ultrasound (EUS) for suspected CBD stone. One-hundred and twelve patients were included, of these fifty-three patients (47.3%) were diagnosed with CBD stone by EUS. Results: In univariate analysis, Age (OR 1.038, P = 0.001), total bilirubin (mg/dl) (OR 1.429, P = 0.02) and CBD width (mm) by US (OR 1.314, P = 0.01) were statistically significant in predicting CBD stone and remained significant in multivariate regression analysis. We developed a diagnostic score that included these three parameters, with assignment of weights for each variable according to the coefficient estimate. A low cut-off score of 0 was associated with sensitivity of 100% for CBD stone, whereas a high cut-off score of 3 was associated with sensitivity of 10% and specificity of 96.6% with a positive predictive value of 67% (ROC of 0.7558). We validated this score with an independent cohort (ROC of 0.7416) with a sensitivity of 46.6%, a specificity of 91.5% and a PPV of 87.1%. Conclusion: We recommend incorporating this score as an aid for stratifying patients with ACC into low or high probability for concomitant CBD stone.