Frailty, Comorbidity, and Associations With In-Hospital Mortality in Older COVID-19 Patients: Exploratory Study of Administrative Data. - Heyl J; Hardy F; Tucker K; Hopper A; Marchã MJM; Navaratnam AV; Briggs TWR; Yates J; Day J; Wheeler A; Eve-Jones S; Gray WK (Interactive journal of medical research, 2022)