Donald Trump may take hydroxychloroquine every day as a preventative against Covid-19, but its effectiveness has not yet been proven. A large study published Friday in the very serious medical journal The Lancet shows on the contrary that neither chloroquine, nor its derivative hydroxychloroquine would be effective against Covid-19 in hospitalized patients. Worse, these molecules even increase the risk of death and cardiac arrhythmia.

Carried out on nearly 15,000 patients, this is the "first large-scale study" to show "robust statistical evidence" that these two treatments that cause so much ink to flow "do not benefit Covid-19 patients "said Dr. Mandeep Mehra, the study's lead author, in a statement.

These patients received four different combinations based on chloroquine (an antimalarial) and hydroxychloroquine (prescribed for rheumatoid arthritis for example). The treatments were either administered alone or combined with an antibiotic from the macrolide family.

The study analyzed data from approximately 96,000 patients infected with the Sars-CoV-2 virus admitted to 671 hospitals between December 20, 2019 and April 14, 2020, discharged or deceased since. About 15,000 of them received one of the four combinations (chloroquine alone or combined with the antibiotic, hydroxychloroquine alone or combined with the same antibiotic), then these four groups were compared to the 81,000 patients in the control group n who have not received this treatment.

NEW Research — No evidence of benefit for #chloroquine and #hydroxychloroquine in # COVID19 patients, urgent randomized trials are needed: finding from a large observational study of nearly 15,000 patients with # COVID19 & 81,000 controls https://t.co/P4YbYVhRDZ

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- The Lancet (@TheLancet) May 22, 2020

Result: the four treatments were all associated with a much higher risk of mortality than in the control group (which was 9.3%): 16.4% of deaths for chloroquine alone, 22.2% when it was combined with the antibiotic; 18% for hydroxychloroquine alone, 23.8% when it was combined with the same antibiotic.

The authors estimate that the risk of mortality is 34% to 45% higher in patients taking these treatments than in patients with comorbidity factors, that is to say risk factors.

They also discovered serious serious cardiac arrhythmias more frequent in patients receiving chloroquine or hydroxychloroquine, especially with the combination hydroxychloroquine / macrolide (8% of the patients against 0.3% in the control group).

The risk of arrhythmia would ultimately be five times higher with the intake of these two molecules, even if the cause and effect link is not directly proven, explain the authors, who request an "urgent" confirmation by clinical trials randomized (patients chosen by lot) before any conclusion.

Pointing out that preliminary small-scale studies have already "failed to identify robust evidence of benefit" from these two treatments, "we now know from our study that the chances of improving" the condition of Covid-19 patients "are rather thin," writes Dr. Frank Ruschitzka, from the Zurich University Hospital, co-author.

While several countries like Brazil are betting on the use of chloroquine and its derivative, the study recommends that these treatments not be administered outside of clinical trials.

Hydroxychloroquine is currently being tested in several clinical trials, including the European Discovery trial.

With AFP

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