Response to the Letter Regarding “Preventing Unnecessary ERCP in Patients With Spontaneous Bile Duct Stone Passage: A Systematic Review and Meta‐Analysis”

We appreciate the opportunity to respond to the thoughtful comments by Dr. Graham on our recently published study, “Preventing Unnecessary ERCP in Patients with Spontaneous Bile Duct Stone Passage: A Systematic Review and Meta-Analysis” [1]. We address the key points below. Our analysis found that common bile duct (CBD) diameter was significantly smaller in patients with spontaneous stone passage. The authors correctly note that the CBD can normally dilate up to 10 mm following cholecystectomy and raises the concern that not stratifying our CBD diameter analysis by cholecystectomy status could confound the results. Among the nine included studies, five reported rates of previous cholecystectomy. These five studies showed no significant difference in prior cholecystectomy rates between groups with and without spontaneous stone passage. Although one study initially reported that the presence of a gallbladder was associated with a higher rate of spontaneous passage (16.9% vs. 3.7%), correction for multiple testing removed this statistical significance [2]. A formal stratified analysis of CBD diameter by cholecystectomy status was not feasible due to insufficient primary data. Nevertheless, we believe the overall finding of an association between smaller CBD diameter and spontaneous passage remains valid. The second concern involves potential work-up bias related to pre-ERCP endoscopic ultrasound (EUS). In some clinical pathways, patients undergo EUS prior to a planned ERCP; if EUS reveals no CBD stone, the patient is classified as having had spontaneous passage, and ERCP is avoided. The exclusion of such patients from studies could indeed underestimate the true incidence of spontaneous passage. In our review, none of the nine included studies described a protocol involving same-session pre-ERCP EUS. All patients with a confirmed CBD stone diagnosis proceeded directly to ERCP without an intervening confirmatory EUS. Therefore, we believe this factor had a negligible impact on the calculated incidence in our meta-analysis. As noted in our study's limitations, the primary determinant of observed passage rates is likely the variation in the time interval between initial stone diagnosis and the performance of ERCP. We sincerely thank Dr. Graham for the valuable feedback, which has allowed us to clarify these points. The authors have nothing to report. The authors declare no conflicts of interest. The authors have nothing to report.