Clinician defined obesity was also included as a comorbidity owing to its probable association with adverse outcomes in patients with covid-19.1112 The clinical information used to calculate prognostic scores was taken from the day of admission to hospital.13 A practical approach was taken to sample size requirements.14 We used all available data to maximise the power and generalisability of our results. Model reliability was assessed by using a temporally distinct validation cohort with geographical subsetting, together with sensitivity analyses.