Current clinical algorithms for predicting common bile duct stones have only moderate accuracy

Abstract

Background & Aims

A risk stratified approach for selecting patients likely to harbor common bile duct (CBD) stones to proceed directly to endoscopic or surgical stone clearance, rather than less invasive testing, has been proposed. We aimed to assess the performance of three clinical algorithms used to predict CBD stones.

Methods

All patients undergoing first-time ERCP in 2011-2012 due to suspected CBD stones were enrolled prospectively in a clinical database. Data such as imaging test findings, liver function tests (LFTs) were collected 48h prior to and on the day of ERCP. Patients were stratified into different risk groups for harboring CBD stones according to three clinical algorithms employing imaging and laboratory data. Findings on ERCP were used as gold standard. The performance characteristics of each algorithm were separately calculated for each time point of LFT assessment.

Results

Overall, 186 patients were analyzed, 75% of who presented CBD stones on ERCP. The proportion of patients categorized as high-risk for harboring CBD stones varied among the three algorithms (67% vs. 73% vs. 56%). Also, the algorithms showed only moderate, albeit comparable, accuracy for predicting the presence of CBD stones (0.65, 95% confidence interval (CI) 0.62-0.68 vs. 0.68, 95%CI 0.63-0.67 vs. 0.59, 95%CI 0.57-0.61). Similar results were obtained when performance characteristics were recalculated using LFTs from 48h prior to ERCP (data not shown).

Conclusion

Three diagnostic algorithms commonly used for predicting CBD stones have comparable but only moderate accuracy. Further research is warranted to improve risk stratification of patients with suspected CBD stones.

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