Postcode Covid-19?

There seems to be a quite extraordinary variation in the mortality rates of people entering NHS hospitals, with a severe Covid-19 infection, in different parts of England (https://www.theguardian.com/world/2020/jul/13/nhs-data-reveals-huge-variation-in-covid-19-death-rates-across-england). Death rates varied from 12.5% (in parts of London) to 80% (in one SW trust). The variation could clearly be partially a consequence of differences in the incidences of the 4 factors (deprivation, ethnicity, gender and underlying health conditions) known to alter the risk of dying from this infection. Having said that, transferring 'best practice' might well improve the performances of hospitals with the worst figures.