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Comparative trials: an ethical issue

Mounting evidence that hydroxychloroquine (Plaquenil°) lacks the efficacy expected in covid-19 has shown the medical and ethical risks of using drugs on the basis of inadequate evidence.

Medical research, its methods, uncertainties, controversies and manipulation have received intense media exposure during the covid-19 pandemic. One of the issues to have generated heated debate concerns the scientific and ethical validity of comparative trials.

According to international scientific consensus, as of the early 21st century, the best way of demonstrating the efficacy of a treatment usually involves conducting comparative trials, preferably with randomisation and blinding. Trials of this type are capable of demonstrating a causal link, rather than just a statistical association, between a treatment and the health outcomes of patients who receive the treatment. For a trial to be ethical, informed consent must be obtained from the participants (a legal obligation), and the study treatment should be compared with the best existing treatment in this situation. But in addition, the trial must be designed and conducted in a way that best ensures reliable results, and there must be genuine uncertainty over the answer to the question addressed by the trial until its completion.

The preliminary studies conducted with hydroxychloroquine (Plaquenil°) back in spring 2020 had not rendered randomised comparative trials of this drug in covid-19 unethical, because these studies had not produced rigorous evidence of its efficacy, which was at best hypothetical. Those who persisted in believing in hydroxychloroquine were misled over the degree of uncertainty surrounding this drug. And the mounting evidence that hydroxychloroquine lacks the efficacy expected in covid-19 showed the very real risks of using drugs on the basis of inadequate evidence.

©Prescrire 1 March 2021

Source: "Comparative trials: an ethical issue" Prescrire International 2021; 30 (224): 82-83. Subscribers only.

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