Development and validation of 'Gallbladder-CBD diameter-Age-Liver function score' to determine the need for...

Endoscopic ultrasound (EUS) can detect significant pathologies in patients with unexplained common bile duct (CBD) dilatation. The aim was to develop and validate a scoring system to identify patients likely to have 'actionable findings (AF)' and will be benefited by EUS examination.

Endoscopic ultrasound database was analyzed from January 2018 to January 2022 to identify patients who underwent EUS for unexplained CBD dilatation (derivation cohort; n = 142). From February 2022 to January 2024, patients were prospectively recruited (validation cohort; n = 230). Demographics, clinical presentation, liver function test (LFT) and imaging findings were noted. Unexplained CBD dilatation was defined as dilated CBD without demonstrable cause on abdominal ultrasound, computed tomography and/or magnetic resonance cholangiopancreatography. Actionable findings, defined as those conditions requiring endoscopic or surgical intervention, were noted. Logistic regression was used to determine predictors of AF. Prediction model was developed using nomogram and validated in the validation cohort.

AF were detected in 57.54% and 50.86% in derivation and validation cohorts, respectively. On multi-variate regression, abnormal gallbladder, p = 0.026, OR = 3.21, CBD diameter = 9-12 mm, p = 0.023, OR = 3.47; CBD diameter = > 12 mm, p = 0.004, OR = 18.0; age > 55 years, p = 0.001, odds ratio (OR) = 7.1 and abnormal LFT, p < 0.0005, OR = 15.82 (GCAL score) predicted AF on EUS. Risk scores were assigned to predictors using nomogram. Nomogram performed well in terms of discrimination with area under curve 0.904, 95% confidence interval (CI) = 0.854-0.954, p < 0.001. At cut-off value of 10.90, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 94.18%, 58.92%, 77.88% 86.84% and 80.28% were obtained in derivation cohort. In validation cohort, sensitivity, specificity, PPV, NPV and accuracy of 95.97%, 83.96%, 90.43%, 87.5% and 94.68% were observed.

EUS can detect 'actionable findings' in patients with unexplained CBD dilatation. 'GCAL score' provides a simple validated risk stratification tool, which can help in selecting patients for EUS examination.