A recent Henry Ford health study showed that patients who were given the drug were less likely to die. Conservative media is all over this bit of news claiming that President Trump has been shown to be right, and that the rest of the media should apologize. In fact, much of the media reporting on this study has failed to mention the critical limitation of this study: It was only a retrospective study.
Don’t get me wrong, retrospective studies are definitely useful, and can help us find correlation. The problem is that they’re not good enough to establish causation. In order to actually determine causation you need to have strict controls over other potential variables, including nefarious problems like selection bias. Without these controls we really cannot say if some other variable is affecting the outcome of patients. Even the study itself had the following warnings on attached to their findings (my emphasis added):
However, our results should be interpreted with some caution and should not be applied to patients treated outside of hospital settings. Our results also require further confirmation in prospective, randomized controlled trials that rigorously evaluate the safety, and efficacy of hydroxychloroquine therapy for COVID-19 in hospitalized patients. Considered in the context of current studies on the use of hydroxychloroquine for COVID-19, our results suggest that hydroxychloroquine may have an important role to play in reducing COVID-19 mortality.
We also have some previous studies which have shown us that hydroxychloroquine was not effective as a treatment for COVID-19. The only thing that is really going to settle the question is a large scale randomized control trial. Until we have such a trial I don’t see how anyone is justified in claiming that hydroxychloroquine is an effective treatment for COVID-19. It’s little more than a premature assessment of a drug without the systematic efforts to determine efficacy.
In the end, regardless of what comes out of any further trials, I think it was still irresponsible of Donald Trump to talk about hydroxychloroquine as if it was some kind of miracle cure. He did not have good evidence that the drug is effective. I don’t care what kind of “good feelings” Trump had about this drug. Follow the data, not your feelings. The real world doesn’t care what your feelings are, and you may be risking lives unnecessarily.