It is well know that doctors have caused more harm than good in certain situations. Such discoveries as that germs on doctors hands increase mortality to cholera being transmitted via water have been ignored by the medical establishment in past centuries. More worryingly, similar things have happened in recent decades.
It was believed, based on observational studies, that hormone-replacement-therapy (HRT) significantly reduces the risk of things such as coronary heart disease and stroke. As such, it was in-cooperated into the Guidelines by the American College of Physicians, making medical best practise, at least in the USA. However, when a randomized control trial was finally done, it turned out to actually increase the risk of heart attacks and strokes. So much so, that the HERS study had to be terminated early because HRT was to dangerous. While this also demonstrates that the medical profession accepts new research and improves itself, it took 8 year from the unproven treatment becoming medical best practise to its negative side effects being shown. During that time, millions of people were treated that increase the risk of the outcome it was meant to prevent.
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