[oldalum]

To underscore BC's point, the reason why therapies of all kinds can seem great in observational studies and then turn out not to be effective in a randomized, blinded, controlled clinical trial is that observational studies generate all sorts of spurious correlations that seem promising, but observational studies cannot establish causality. So those early observational studies of HCQ looked great but the positive findings turned out to be spurious (i.e., wrong). In general, observational studies can be useful in generating hypotheses that can be studied in randomized controlled trials, but they are not evidence of effectiveness. A point lost on the HCQ promoters, including our departing leader. And as a consequence, many people were exposed to the potential harms of the drug in exchange for no benefit, and supplies grew short for those who needed the drug to treat certain autoimmune diseases for which it has been proven effective.

[oldalum]

To underscore BC's point, the reason why therapies of all kinds can seem great in observational studies and then turn out not to be effective in a randomized, blinded, controlled clinical trial is that observational studies generate all sorts of spurious correlations that seem promising, but observational studies cannot establish causality. So those early observational studies of HCQ looked great but the positive findings turned out to be spurious (i.e., wrong). In general, observational studies can be useful in generating hypotheses that can be studied in randomized controlled trials, but they are not evidence of effectiveness. A point lost on the HCQ promoters, including our departing leader. And as a consequence, many people were exposed to the potential harms of the drug in exchange for no benefit, and supplies grew short for those who needed the drug to treat certain autoimmune diseases for which it has been proven effective.