I had this same question early on and I recall reading somewhere that treated hypertension reduced risk. Ostensibly, even if that was from a credible source, it may not mean much though.
The problem is that the relationship between hypertension, antihypertensives, and Covid is going to be very nuanced and difficult to ascertain without large patient populations to study. One of the very unique aspects of the Covid pandemic is that the NPIs seem to be very effective at damping the spread, so much so that the pool of patients to study keeps moving from region to region every 60 days or so.
By the time you design a study, recruit a pool and wait for some of them to get covid, not enough get it for the study to have enough statistical power.
