Sensitivity and specificity of clinical, biochemical, and radiological predictors of common bile duct stones in patients who underwent endoscopic retrograde cholangiopancreatography: a binary logistic regression analysis

Background: Gallbladder stones are one of the most common of today's health-related problems. Prediction of Common Bile Duct Stones (CBDS) permits better management of those patients. Objective: The aim of this study was to determine the sensitivity and specificity of various predictors of CBDS. Methods: This cross-sectional study was conducted on patients who underwent Endoscopic Retrograde Cholangiopancreatography (ERCP) for suspected CBDS at King Fahd Hospital of the University (Al-Khobar, Saudi Arabia from 2006 to 2018. Based on the presence or absence of specific predictive features as per the American Society for Gastrointestinal Endoscopy (ASGE) guidelines, we stratified the patients into high, intermediate, and low-risk of harboring CBDS. Data were analyzed by IBM© SPSS© version 21, using Chisquare test, Mann–Whitney U test, Wilcoxon signed rank test, and receiver operating characteristic curve analysis. Also, binary logistic regression was performed to determine the independent predictors, and p-value <0.05 was considered statistically significant. Sensitivity, specificity, likelihood ratios, accuracy, positive predictive value, and negative predictive value were calculated for potential predictors of CBD stones. Results: One hundred forty-two patients were included in the study, 76 patients (53.5%) had choledocholithiasis [64.4% males, 45.8% females (p=0.028)] and 66 patients (46.5%) had normal CBD on endoscopic retrograde cholangiopancreatography. In the choledocholithiasis group, the proportion of jaundice was significantly higher 61% (p=0.037), abdominal pain was reported in 54.7% of the patients (p=0.126), itching in 75% (p=0.119), change in the color of stool and urine was reported in 57.1% (p=0.718), 61.4% (p=0.209) of the patients, respectively. Positive Murphy's sign was seen in 37.4% of the patients who had CBDS (p=0.234). Visualization of CBD stones on trans-abdominal ultrasonography was the best predictor for the presence of CBDS (adjusted OR: 4.744, sensitivity: 34%, specificity: 92%, p<0.0001), followed by CBD diameter (adjusted OR: 1.350, sensitivity: 82%, specificity: 49%, p=0.000). Among Liver function tests (LFTs), total bilirubin >1.8 mg/dl, direct bilirubin >2 mg/dl, GGTP >281 U/L, and ALP >149 U/L are considered reliable predictors for choledocholithiasis. Conclusion: Visualization of CBD stones on trans-abdominal ultrasonography was the best predictor for the presence of CBDS followed by CBD diameter. CBD diameter ≥7 mm on ultrasonography in cases that the patient did not undergo cholecystectomy and more than 1 cm in cases that the patient underwent cholecystectomy are suggestive of CBDS. In presence of either conditions, we suggest proceeding to more invasive and therapeutic procedures such as ERCP.