“ Prior studies had fewer than 20 COVID-19 patients with SLE and/or RA; this study had 159.”
Out of how many patients? How many went on to develop symptoms? How many got better faster?
That’s practically a statistically insignificant number and you can’t make an assumption about the exposure levels of the other (not mentioned) patients who didn’t get it.
TL:DR - it’s a vapid study.
In other words they didn't really study HCQ use for COVID, they had a database and they did some statistis and got a result. This is the sort of work that results in 'Coffee linked with high testosterone in construction workers born in August" articles. Oh, they found some correlation at some level using data not controlled for the things they are saying they found.
Here they found 159 people who have Lupus or rheumatoid arthritis and got COVID (just 159!) and half of them were on HCQ. So based on those 80 people we now know that HCQ is bunk. Got it.