SnapChole: An International, Time-Bound Prospective Platform Study of Management Strategies and Outcomes in Acute Calculous Cholecystitis (SnapChole)

This study aims to understand how different treatment approaches for acute gallbladder inflammation (acute calculous cholecystitis) affect patient outcomes in real-world hospital settings.

Acute calculous cholecystitis is a common condition that occurs when gallstones block the gallbladder and cause infection or inflammation. In more severe cases, patients may develop organ dysfunction, and doctors must decide quickly how best to treat the condition. Treatment options include early surgery to remove the gallbladder, placement of a drainage tube, or treatment with antibiotics alone. The best approach is not always clear, especially for patients who are older, have other medical conditions, or are very unwell.

This study will collect information from hospitals around the world about how patients with severe gallbladder inflammation are treated as part of their usual care. No treatments are assigned by the study. All decisions are made by the patient's clinical team.

The goal is to compare outcomes between different treatment approaches in patients who could reasonably receive more than one option. The study will examine recovery, survival, need for additional procedures, and time spent in the hospital over 90 days.

The findings are intended to help doctors and patients better understand which treatment strategies may lead to better outcomes in different clinical situations, and to improve decision-making in emergency surgical care.

Study Overview

• Status: Not yet recruiting
• Conditions: Cholecystitis, Acute

Detailed Description

SnapChole is an international, multicenter, prospective, time-bound observational platform study designed to evaluate management strategies and outcomes in adults with acute calculous cholecystitis. The study focuses on patients with severe disease, defined by the presence of organ dysfunction, in whom treatment decisions are influenced by both patient-level factors and system-level capability.

The study is conducted as a prospective clinical audit using routinely collected data and does not alter patient care. Participating centers enroll consecutive eligible patients during a predefined local accrual window. Data are recorded contemporaneously using standardized case report forms and transferred in deidentified form to a central coordinating database. Follow-up extends to 90 days from the index presentation.

The study architecture separates descriptive benchmarking from causal analysis. The full cohort provides a denominator population for characterization of treatment patterns, timing of interventions, and outcomes across centers and healthcare systems. Within this cohort, prespecified analytic subsets are defined at the point of clinical decision-making (time zero), corresponding to the moment at which the treating team determines that one or more management strategies are feasible.

Comparative analyses are structured to align eligibility, treatment assignment, and follow-up, consistent with a target trial emulation framework applied to observational data. Treatment strategies of interest include early cholecystectomy, gallbladder drainage as an initial approach, and antimicrobial-only management. Analyses are restricted to patients in whom the relevant strategies are simultaneously available, in order to reduce bias arising from differences in clinical eligibility or institutional capability.

Exposure is defined as completion of the assigned management strategy within a prespecified interval following the decision point, reflecting real-world delivery of care. Outcomes include days alive and out of hospital at 90 days, mortality, need for additional interventions, and time to achieved source control.

The study also incorporates complementary analyses, including benchmarking of care pathways, evaluation of patient-centered outcomes, and assessment of factors influencing clinical decision-making. Together, these components are intended to provide a comprehensive understanding of how management strategies are selected and how they relate to outcomes in severe acute calculous cholecystitis.

• Study Type: Observational
• Enrollment (Estimated): 1500

Contacts and Locations

• Study Contact: Name: Gary A Bass, MD, PhD; Phone Number: 2672168309; Email: gary.bass@pennmedicine.upenn.edu
• Study Contact Backup: Name: Stefano PB Cioffi, MD, PhD; Phone Number: 2672168309; Email: stefanopiero.cioffi@ospedaleniguarda.it

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Hospital of the University of Pennsylvania
      • Contact: Gary A Bass, MD, PhD; Phone Number: 2672168309; Email: gary.bass@pennmedicine.upenn.edu
      • Contact: Christine; Phone Number: +12152400454; Email: garybassmd@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adults with severe acute calculous cholecystitis (Tokyo Guidelines 2018 Grade III) presenting to participating centers and managed under routine clinical care. The population reflects patients in whom treatment decisions are influenced by physiologic severity, comorbidity, and institutional capability. Consecutive eligible patients are enrolled prospectively to define a real-world denominator cohort. Analytic subsets are subsequently defined at the attending surgeon-level decision point to evaluate treatment strategies under conditions in which alternative approaches are simultaneously feasible.

Description

Inclusion Criteria:

• Age ≥18 years
• Presentation with suspected acute calculous cholecystitis
• Diagnosis confirmed prospectively according to Tokyo Guidelines 2018 (TG18) diagnostic criteria
• Classified as severe (TG18 Grade III) disease based on the presence of organ dysfunction
• Managed at a participating center during the study accrual period

Exclusion Criteria:

• Acalculous cholecystitis
• Isolated choledocholithiasis or acute cholangitis without cholecystitis
• Primary gallstone pancreatitis without concomitant acute cholecystitis
• Elective admission for chronic biliary symptoms
• Prior cholecystectomy

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Full Platform Cohort; Consecutive adult patients presenting with acute calculous cholecystitis and meeting Tokyo Guidelines 2018 diagnostic criteria, including those with severe (Grade III) disease. This cohort represents the full prospective denominator population and is used for benchmarking of treatment patterns, timing of interventions, and clinical outcomes under routine care. No restrictions are applied based on treatment strategy eligibility.
Dual-Eligible Cohort (Surgery vs Drainage); Subset of patients with severe acute calculous cholecystitis (Tokyo Guidelines 2018 Grade III) in whom both early cholecystectomy and gallbladder drainage are judged feasible and available at the attending surgeon-level decision point (time zero). This cohort forms the analytic population for target trial emulation comparing operative source control with drainage-first strategies. Eligibility is defined prior to treatment assignment.
Nonoperative-Eligible Cohort (Drainage vs Antibiotics); Subset of patients with severe acute calculous cholecystitis (Tokyo Guidelines 2018 Grade III) not selected for immediate surgery but in whom both drainage-first and antimicrobial-only management are feasible at the time of decision. This cohort forms the analytic population for target trial emulation comparing nonoperative management strategies. Eligibility is defined at time zero prior to treatment initiation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Days alive and out of hospital at 90 days	Number of days the participant is alive and not hospitalized during the 90 days following time zero, defined as the attending surgeon-level decision point at which treatment strategy is assigned. Higher values indicate better recovery.	90 days from time zero (attending surgeon-level decision point)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
All-cause mortality	Death from any cause within the specified follow-up period after time zero, defined as the attending surgeon-level decision point at which treatment strategy is assigned.	90 days from time zero
Failure of Source Control	Persistent or recurrent sepsis requiring escalation of intervention, including conversion to surgery, additional drainage procedures, or reoperation following the initial management strategy.	Within 90 days from time zero
Unplanned biliary reintervention	Any unplanned procedural intervention related to biliary disease, including repeat drainage, operative intervention, or endoscopic procedures following the initial management strategy.	within 90 days of time zero
Length of hospital stay	Total duration of the index hospital admission measured from admission to discharge.	From hospital admission to hospital discharge, assessed up to 90 days from time zero
Time to achieved source control	Elapsed time from time zero to completion of the definitive source-control intervention, including surgical or drainage procedures.	From time zero to completion of source-control intervention, assessed up to 90 days

Collaborators and Investigators

• Sponsor: European Society for Trauma and Emergency Surgery
• Collaborators: University of Pennsylvania
• Investigators: Study Chair: Gary A Bass, MD, PhD, University of Pennsylvania

Publications and helpful links

General Publications

• Yokoe M, Hata J, Takada T, Strasberg SM, Asbun HJ, Wakabayashi G, Kozaka K, Endo I, Deziel DJ, Miura F, Okamoto K, Hwang TL, Huang WS, Ker CG, Chen MF, Han HS, Yoon YS, Choi IS, Yoon DS, Noguchi Y, Shikata S, Ukai T, Higuchi R, Gabata T, Mori Y, Iwashita Y, Hibi T, Jagannath P, Jonas E, Liau KH, Dervenis C, Gouma DJ, Cherqui D, Belli G, Garden OJ, Gimenez ME, de Santibanes E, Suzuki K, Umezawa A, Supe AN, Pitt HA, Singh H, Chan ACW, Lau WY, Teoh AYB, Honda G, Sugioka A, Asai K, Gomi H, Itoi T, Kiriyama S, Yoshida M, Mayumi T, Matsumura N, Tokumura H, Kitano S, Hirata K, Inui K, Sumiyama Y, Yamamoto M. Tokyo Guidelines 2018: diagnostic criteria and severity grading of acute cholecystitis (with videos). J Hepatobiliary Pancreat Sci. 2018 Jan;25(1):41-54. doi: 10.1002/jhbp.515. Epub 2018 Jan 9.
• Pisano M, Allievi N, Gurusamy K, Borzellino G, Cimbanassi S, Boerna D, Coccolini F, Tufo A, Di Martino M, Leung J, Sartelli M, Ceresoli M, Maier RV, Poiasina E, De Angelis N, Magnone S, Fugazzola P, Paolillo C, Coimbra R, Di Saverio S, De Simone B, Weber DG, Sakakushev BE, Lucianetti A, Kirkpatrick AW, Fraga GP, Wani I, Biffl WL, Chiara O, Abu-Zidan F, Moore EE, Leppaniemi A, Kluger Y, Catena F, Ansaloni L. 2020 World Society of Emergency Surgery updated guidelines for the diagnosis and treatment of acute calculus cholecystitis. World J Emerg Surg. 2020 Nov 5;15(1):61. doi: 10.1186/s13017-020-00336-x.
• Bass GA, Kaplan LJ, Ryan EJ, Cao Y, Lane-Fall M, Duffy CC, Vail EA, Mohseni S. The snapshot audit methodology: design, implementation and analysis of prospective observational cohort studies in surgery. Eur J Trauma Emerg Surg. 2023 Feb;49(1):5-15. doi: 10.1007/s00068-022-02045-3. Epub 2022 Jul 15.
• Hernan MA, Robins JM. Using Big Data to Emulate a Target Trial When a Randomized Trial Is Not Available. Am J Epidemiol. 2016 Apr 15;183(8):758-64. doi: 10.1093/aje/kwv254. Epub 2016 Mar 18.
• Okamoto K, Suzuki K, Takada T, Strasberg SM, Asbun HJ, Endo I, Iwashita Y, Hibi T, Pitt HA, Umezawa A, Asai K, Han HS, Hwang TL, Mori Y, Yoon YS, Huang WS, Belli G, Dervenis C, Yokoe M, Kiriyama S, Itoi T, Jagannath P, Garden OJ, Miura F, Nakamura M, Horiguchi A, Wakabayashi G, Cherqui D, de Santibanes E, Shikata S, Noguchi Y, Ukai T, Higuchi R, Wada K, Honda G, Supe AN, Yoshida M, Mayumi T, Gouma DJ, Deziel DJ, Liau KH, Chen MF, Shibao K, Liu KH, Su CH, Chan ACW, Yoon DS, Choi IS, Jonas E, Chen XP, Fan ST, Ker CG, Gimenez ME, Kitano S, Inomata M, Hirata K, Inui K, Sumiyama Y, Yamamoto M. Tokyo Guidelines 2018: flowchart for the management of acute cholecystitis. J Hepatobiliary Pancreat Sci. 2018 Jan;25(1):55-72. doi: 10.1002/jhbp.516. Epub 2017 Dec 20.
• Loozen CS, van Santvoort HC, van Duijvendijk P, Besselink MG, Gouma DJ, Nieuwenhuijzen GA, Kelder JC, Donkervoort SC, van Geloven AA, Kruyt PM, Roos D, Kortram K, Kornmann VN, Pronk A, van der Peet DL, Crolla RM, van Ramshorst B, Bollen TL, Boerma D. Laparoscopic cholecystectomy versus percutaneous catheter drainage for acute cholecystitis in high risk patients (CHOCOLATE): multicentre randomised clinical trial. BMJ. 2018 Oct 8;363:k3965. doi: 10.1136/bmj.k3965.

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: April 23, 2026
• First Submitted That Met QC Criteria: April 29, 2026
• First Posted (Actual): May 5, 2026

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: cholecystectomy; high-risk; cholecystitis; percutaneous cholecystostomy; target trial emulation
• Additional Relevant MeSH Terms: Digestive System Diseases; Biliary Tract Diseases; Gallbladder Diseases; Cholecystitis; Cholecystitis, Acute
• Other Study ID Numbers: SnapChole

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Deidentified individual participant data are collected as part of a prospective international clinical audit and stored in a secure centralized database. Data sharing policies will be developed in accordance with applicable data protection regulations, including GDPR and HIPAA, and will be governed by the study steering committee. Requests for data access may be considered following publication of primary analyses, subject to institutional agreements and ethical approvals.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No