Quantifying the association between COVID-19, ethnicity and mortality: A cohort study across three UK national databases

Purpose: Early evidence suggests increased severity of COVID-19 disease amongst Black, Asian and Ethnic minority (BAME) groups. There is limited evidence from population-based cohorts at scale across the UK or internationally that quantify within BAME group differences, or examine these in relation to modifiable risk factors. Aim: To describe the prevalence of confirmed COVID-19 cases by ethnic group in a large and representative sample of UK adults, and to quantify the association between ethnicity and mortality stratified by COVID-19 infection and modifiable clinical and social risk factors (blood pressure, HbA1c level, total cholesterol, Body Mass Index, smoking status, co-morbidities, medication use, domicile and household number). Methods: A cohort study of adults registered across three large national primary care databases in England with over 5000 practices representing over 40% of the UK population. Participant sociodemographic, deprivation, clinical and domicile characteristics will be summarised and compared by higher level ethnic group (White, Black, Asian and Mixed Other) and their subgroups. For example, the Asian subgroup includes Pakistani, Indian, Bangladeshi or Chinese while the Black subgroup includes African or Carribean as per the 2011 census. Hazard ratios and 95% confidence intervals for all-cause mortality and COVID-19 mortality, adjusted for potentially confounding factors will be calculated using Cox's proportional hazard regression. Implication: Our findings could provide rapid evidence on patterns of COVID-19 and associated mortality across and within ethnic groups in the UK. This has the potential to inform targeted mitigation public health strategies, and could alter clinical thresholds for at-risk patients presenting with the infection.