Title: RISK FACTORS FOR NECROTIC CHOLECYSTITIS DURING COVID-19 PANDEMIC: THE ChoCO WSES PROSPECTIVE MULTICENTER OBSERVATIONAL STUDY Short title: The ChoCO (Cholecystitis under COVID-19 pandemic) WSES STUDY

STEERING COMMITTEE: • Prof. Elie Chouillard, Service de Chirurgie Générale, Digestive, Metabolique • Centre Hospitalier de Poissy/Saint-Germain-en-Laye, France; • Prof. Fausto Catena, University Hospital of Parma, Italy; • Prof. Salomone Di Saverio, Department of General Surgery, University of Insubria, University Hospital of Varese, ASST Sette Laghi, Regione Lombardia, Varese, Italy; • Prof. Yoram Kluger, Rambam Medical Centre, Haifa, Israel; • Prof. Ernest E. Moore, Trauma Surgery, Denver Health, Denver, CO, USA; • Prof. Carlos Augusto Gomes, Hospital Universitário Terezinha de Jesus, Faculdade de Ciências Médicas e da Saúde de Juiz de Fora (SUPREMA), Juiz de Fora, Brazil; • Massimo Sartelli, MD, Macerata Hospital, Italy; • Mauro Podda, MD, Department of Emergency Surgery, Cagliari University Hospital, Cagliari, Italy; • Federico Coccolini, MD, University Hospital of Pisa, Italy • Prof. Luca Ansaloni, Bufalini Hospital, Cesena, Italy • Prof. Fikri Abu-Zidan, College of Medicine and Health Sciences, UAE University, AlAin, United Arab Emirates; • Prof Walter Biffl, Scripps Memorial HospitalLa Jolla; La Jolla, CA USA