biostudies-literatureHohl CMPublic Health Agency of Canada/COVID-19 Immunity Task ForceFonds de recherche du Québec – SantéOntario Ministry of Colleges and UniversitiesSaskatchewan Health Research FoundationBioTalent CanadaGenome British ColumbiaFondation du CHU de QuébecBC Academic Health Science NetworkCanadian Institutes of Health Researche083280https://www.ebi.ac.uk/biostudies/studies/S-EPMC11580276biostudies-literatureUnknown14(11)<h4>Objective</h4>The objective is to externally validate and assess the opportunity to update the Canadian COVID-19 Mortality Score (CCMS) to predict in-hospital mortality among consecutive non-palliative COVID-19 patients infected with Omicron subvariants at a time when vaccinations were widespread.<h4>Design</h4>This observational study validated the CCMS in an external cohort at a time when Omicron variants were dominant. We assessed the potential to update the rule and improve its performance by recalibrating and adding vaccination status in a subset of patients from provinces with access to vaccination data and created the adjusted CCMS (CCMS^adj). We followed discharged patients for 30 days after their index emergency department visit or for their entire hospital stay if aBMJ openAccuracy of the Canadian COVID-19 Mortality Score (CCMS) to predict in-hospital mortality among vaccinated and unvaccinated patients infected with Omicron: a cohort study.PMC11580276N/A2122-HQ-00005444767953574007C-655-2129VAC007COV024Clark GMcRae AGrant LDahn TStachura MChandra KKhangura JDaoust RRowe BMohindra RDavis PCCEDRRN investigators for the Network of Canadian Emergency Researchers and the Canadian Critical Care Trials GroupWiemer HHaward JTaylor JTurner JYeom DSBrar BMartin IArchambault PMFok PWelsford MLandes MCheng IOhle RWormsbecker STing DYan JArsenault KPerry JRobert SMorrison LJHohl CMCampbell SMercier EGraham LVandenBerg SJelic TScheuermeyer FPurssell EBrooks SCRosychuk RLin KfalseAccuracy of the Canadian COVID-19 Mortality Score (CCMS) to predict in-hospital mortality among vaccinated and unvaccinated patients infected with Omicron: a cohort study.<h4>Objective</h4>The objective is to externally validate and assess the opportunity to update the Canadian COVID-19 Mortality Score (CCMS) to predict in-hospital mortality among consecutive non-palliative COVID-19 patients infected with Omicron subvariants at a time when vaccinations were widespread.<h4>Design</h4>This observational study validated the CCMS in an external cohort at a time when Omicron variants were dominant. We assessed the potential to update the rule and improve its performance by recalibrating and adding vaccination status in a subset of patients from provinces with access to vaccination data and created the adjusted CCMS (CCMS^adj). We followed discharged patients for 30 days after their index emergency department visit or for their entire hospital stay if a2024-01-01T00:00:00Z2024 Nov2025-04-04T13:41:12.9Z2025-04-04T13:41:12.9ZS-EPMC115802763956694210.1136/bmjopen-2023-083280