A group of 37 Brazilian, American and British specialists will release this Saturday, 22, an open letter to challenge the conclusions of clinical trials published in important scientific journals on the early treatment of Covid-19 with hydroxychloroquine.
Led by Marcio Watanabe, professor in the Statistics department at Universidade Federal Fluminense, the team that drafted the document includes statisticians, mathematicians and doctors, from institutions such as the University of São Paulo, Federal University of Rio de Janeiro, Federal University of Pernambuco, University of Chicago, University of Paris and University of Oxford.
The criticized works involved renowned journals: Annals of Internal Medicine , Clinical Infectious Diseases and New England Journal of Medicine . These studies tested the use of hydroxychloroquine in adults with Covid-19 at an early stage of the disease (not hospitalized, therefore) and concluded that there was no benefit in the use of medication among patients.
“We saw limitations in the interpretation of the data, which ended up interfering negatively in the conclusions related to the symptoms”.Marcio Watanabe
According to the letter’s authors, data from randomized trials on early treatment in outpatients published so far actually show favorable effects in groups receiving therapy, especially in high-risk patients, such as the elderly, where action was up to three times higher than in young people. But as most samples were made up of young people without comorbidities, the studies would be statistically inconclusive, and therefore there would still be reasonable uncertainty about the results.
According to them, instead of the papers reporting this, they claim that the treatment had no effect compared to the placebo. “This misinterpretation in statistical tests is well known and explained in most undergraduate books in the field,” says Watanabe. “An article published in Nature last year, it claims that about 51% of studies on clinical trials with this type of result have incorrect conclusions. ”
Other observations would not have been made, such as in relation to the time elapsed between the infection and the beginning of the treatment. In the New England study , for example, the results were general, mixing all patients and averaging. In the analysis of the letter’s authors, if hydroxychloroquine is administered on the day of exposure to the virus, for example, the reduction in people with symptoms could be up to 72%, but the effect would decrease the longer it takes to start treatment. “We are not saying that medication is the cure for the disease. We want the studies to rectify their conclusions, indicating precisely the positive effects that hydroxychloroquine had on the data, neither more nor less ”, says Cláudia Paiva, from the Federal University of Rio de Janeiro.
The authors of the open letter have studied several issues related to the new coronavirus since the beginning of the first cases in the world. Interest in hydroxychloroquine has emerged more recently, with the great controversy surrounding the drug.
“The sad politicization of this medicine has created unusual obstacles in science”, says Flavio Abdenur, a mathematician from the National Institute of Pure and Applied Mathematics.