I would be careful not to confuse correlation with causation here. Most old people have medical conditions. For example, about 75% of older people have high blood pressure [1] so seeing a 75% rate in the virus fatalities should not mean much.

I suspect age and immune function drive mortality, and the other factors are merely along for the ride.

[1] https://www.uptodate.com/contents/treatment-of-hypertension-...