LONDON • The malaria drug hydroxychloroquine, which US President Donald Trump says he has been taking and has urged others to use, was tied to increased risk of death in hospitalised Covid-19 patients, according to a large study published in the medical journal Lancet.
In the study that looked at over 96,000 people hospitalised with Covid-19, those treated with hydroxychloroquine or the related chloroquine had higher risk of death than patients who were not given the medicines.
The authors of the study said they could not confirm whether taking the drugs resulted in any benefit for coronavirus patients.
"Urgent confirmation from randomised clinical trials is needed," they wrote.
The trial was not placebo-controlled, generally considered the gold standard for clinical data.
Hospitalised patients tend to have a more severe version of Covid-19.
Some proponents of the drugs as a treatment argue that they may need to be administered at an earlier stage in order to be effective.
There are ongoing randomised, controlled clinical trials to study hydroxychloroquine's effectiveness in preventing coronavirus infection as well as treating mild to moderate Covid-19. Some of those trials may yield results within weeks.
The US Department of Veterans Affairs (VA) has treated 1,300 Covid-19 patients with hydroxychloroquine, according to a document released on Friday by Senate Democratic leader Chuck Schumer, who received the information from the VA in response to questions he submitted.
The VA said it was not pressured into using hydroxychloroquine by the White House, the Department of Health and Human Services or any other federal agency. "VA, like so many medical facilities across this nation, is in a race to keep patients alive during this pandemic, and we are using as many tools as we can," it said.
Demand for the decades-old hydroxychloroquine has surged as Mr Trump repeatedly pushed for its use against the coronavirus. "What have you got to lose?" he said.
Mr Trump says he has been taking the drug as a "preventative medicine", despite a lack of scientific evidence.
The Lancet study authors suggested the medicines should not be used to treat Covid-19 outside of clinical trials until those studies confirm their safety and efficacy for patients.
The US Food and Drug Administration has said hydroxychloroquine should be used only for hospitalised Covid-19 patients or those in clinical trials. The drug has been tied to dangerous heart rhythm problems.
The Lancet study looked at data from 671 hospitals, where 14,888 patients were given either hydroxychloroquine or chloroquine, with or without an antibiotic, and 81,144 patients who were not treated with those drugs.
Both drugs have shown evidence of being effective against the coronavirus in a lab setting, but studies in patients have proven inconclusive at best.
In Singapore, Associate Professor David Lye, senior consultant and director of the Infectious Disease Research and Training Office at the National Centre for Infectious Diseases (NCID), said: "There is increasing evidence that anti-malarial drugs do not work. We have stopped using it at NCID for quite a while now."
Several small studies in Europe and China spurred interest in using hydroxychloroquine against Covid-19, but were criticised for lacking scientific rigour.
Several more recent studies have not shown the drug to be an effective treatment for the disease. In the past week, two studies in the medical journal BMJ showed that patients given hydroxychloroquine did not improve significantly over those who were not.
Besides malaria, hydroxychloroquine is used to treat lupus and rheumatoid arthritis.