The US president drew criticism from medical officials this week when he announced that he was taking the antimalarial drug hydroxychloroquine as a preventative medicine, asking: "What do you have to lose?" After accounting for demographic factors and pre-existing conditions, the team calculated that treatment with this combination of drugs is associated with a more than five-fold increase in risk of developing a serious heart arrhythmia while in hospital (as an example, an increase from 0.3% to 1.5% would be attributable to the drug regimen after adjustment for other clinical factors).
Yet Trump has made clear that, at least when it comes to hydroxychloroquine, he has prioritized anecdotal evidence, including a letter he told reporters he'd received from a doctor in Westchester, New York, claiming success with the drug.
The drugs are approved for treating lupus and rheumatoid arthritis and for preventing and treating malaria, but no large rigorous tests have found them safe or effective for Covid-19.
Further, the researchers concluded that they were unable to "confirm a benefit of hydroxychloroquine or chloroquine when used alone or with a macrolide, on in-hospital outcomes for COVID-19".
According to the worldwide news agency, The death rates of the treated groups were: hydroxychloroquine 18%; chloroquine 16.4%; control group 9%. Patients who received hydroxychloroquine alone had a 34% increase in mortality risk and a 137% increase in risk of irregular heartbeat.
"Each of these drug regimens was associated with decreased in-hospital survival and an increased frequency of ventricular arrhythmias when used for treatment of COVID-19".
The US president still insists that the use of HCQ to fight COVID-19 is a "game changer" and he slammed an earlier non-peer reviewed study that found a link between the use of the antimalaria drug and an increasing number of deaths among corona-stricken veterans.
Those who were treated with hydroxychloroquine with a macrolide had a mortality rate of 23.8 percent.
"The FDA is aware of reports of serious heart rhythm problems in patients with COVID-19 treated with hydroxychloroquine or chloroquine, often in combination with azithromycin", the agency said.
Authors of a separate study that supported the use of antimalaria drugs with antibiotics for Covid requested that their paper be withdrawn, according to the Retraction Watch website.
Mr Trump says he has not tested positive for Covid-19 and is taking the drug because he thinks it has "positive benefits".
Dr Stephen Griffin, associate professor in the school of medicine, University of Leeds, said the paper was "potentially a landmark study for Covid-19 therapy". A study of 368 US veterans also showed that the drugs might be potentially harmful.
Hydroxychloroquine is a commonly used drug to treat malaria, but has been dubiously linked to curing coronavirus.
Trump's endorsement has led many people to take the medications without scientific proof of their benefit.