A–D, The mortality rates of patients with coronavirus disease 2019 (COVID-19) in each Coronavirus Clinical Characterisation Consortium (4C) mortality score risk group (low, intermediate, high, and very high) are compared in each age group (A), in each epidemic wave period (B), in patients aged <75 years in each epidemic wave period (C), and in patients aged ≥75 years in each epidemic wave period (D).