How many are at increased risk of severe COVID-19 disease? Rapid global, regional and national estimates for 2020

Andrew Clark; Mark Jit; Charlotte Warren-Gash; Bruce Guthrie; Harry HX Wang; Stewart W Mercer; Colin Sanderson; Martin McKee; Christopher Troeger; Kanyin I Ong; Francesco Checchi; Pablo Perel; Sarah Joseph; Hamish P Gibbs; Amitava Banerjee; Rosalind M Eggo

In addition to providing estimates for , the studies in Scotland and Southern China were also used to calculate the multimorbidity fraction i.e. the proportion of individuals with multiple (two or more) underlying conditions among those with at least one, by age group and sex. All analyses were done using disease categories that matched as closely as possible to the COVID-19-relevant categories defined in our analysis. In both studies this included: CVD (defined as the presence of one or more of coronary heart disease, hypertension, cerebrovascular disease, peripheral arterial disease, heart failure, or atrial fibrillation); chronic neurological disease (defined as one or more of dementia, multiple sclerosis and Parkinson's disease); and CRD (defined as one or both of chronic obstructive pulmonary disease and bronchiectasis). Other COVID-related conditions listed above were counted separately. The GBD provide separate estimates for hypertensive heart disease and CKD due to hypertension, but it was not possible to make this distinction in the multimorbidity datasets, so all hypertension was included in the CVD category.