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.

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.

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

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.

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.