Timing, case ascertainment, inclusion and exclusion criteria
We reviewed HES data for all completed episodes of hospital care in
England with a discharge date from 1st March to
31st October 2020 that involved a diagnosis of
COVID-19. Patients aged < 18 years were excluded. Cases of
COVID-19 were identified using the International Statistical
Classification of Disease and Related Health Problems
10th edition (ICD-10) codes U071 and U072.
Critical care (high dependency unit (HDU) or intensive care unit (ICU))
admissions and those receiving advanced respiratory support were
identified.