Hey now, be careful!
It’s no wonder that this work [use of hydroxychloroquine for COVID-19] has set off so many arguments: statistically, it’s like a funhouse mirror. Here, though, is where some of the folks pinging me on Twitter and sending me emails tend to get more worked up, especially to that point about anecdotal data. I can see where they’re coming from: if you haven’t done this stuff, you can look at a report of people responding to such a treatment and figure that the answer is here – right here, and anyone who doesn’t see it must have some ulterior motives in ignoring what’s in front of their face. But that’s not how it works.
It’s weird and startling, though, if you haven’t had the opportunity to go back through clinical research (and even patient treatment) and seen how many things looked like they worked and really didn’t. It happens again and again. Alzheimer’s drugs, obesity drugs, cardiovascular drugs, osteoporosis drugs: over and over there have been what looked like positive results that evaporated on closer inspection. After you’ve experienced this a few times, you take the lesson to heart that the only way to be sure about these things is to run sufficiently powered controlled trials. No short cuts, no gut feelings – just data.
You get that good data via double-blind randomized controlled trials.
David also referenced a worrisome study. The combo of hydroxychloroquine and metformin in mice caused 30% mortality. Many human type 2 diabetics take metformin.
Source: Hydroxychloroquine Update For April 6 | In the Pipeline
Steve Parker, M.D.
Advanced Mediterranean Diet 
Thank you!