I'd have thought population density was important. London and New York for example have similar populations, but London although badly affected is much less so than New York.
Some arguing over what is the best measure death rate per million/hundred thousand, shows UK not as badly affected as many countries,and US faring better, but simple cumulative totals show US really badly affected with no population data.
Also rate per reported cases doesn't account for different testing levels.
One thing that has surprised me is watching all of the horror stories of Italy and Spain, and China to some extent on the news, but not seeing the same reporting here now we have similar death rates.
Either other countries health services were being overwhelmed nore, or our media are being silenced? Or perhaps the disease is more geographically widespread here than other places meaning numbers are high overall, but no single area being overwhelmed (London closest to being overwhelmed)?