> The increase in risk was not confined to the elderly and was not uniform across ethnicities > Rate ratios comparing patients with covid-19 and matched contro

> The increase in risk was not confined to the elderly and was not uniform across ethnicities > Rate ratios comparing patients with covid-19 and matched controls were greater in individuals aged less than 70 than those aged 70 or more for all outcomes > An alternative approach might have involved comparing outcomes after covid-19 and other hospital admissions; such research has recently been conducted with similar data sources to those in our own study (although with a smaller covid-19 cohort), and comparable rates of organ dysfunction were found between patients with covid-19 and patients with pneumonia who were discharged from hospital in 2019.36 We believe that our study design, where comparisons were made with the expected risk in the general population, was more relevant to public health policy, and complementary to the study that used non-covid hospital admissions as the comparison group. Also, the use of non-covid hospital admissions as the comparison group does not allow estimation of excess morbidity because non-covid admission does not necessarily represent an appropriate counterfactual situation to admission to hospital for covid-19, and the size and direction of the inferences will depend on the choice of control admissions.