There has been no clinical trial proving hydroxychloroquine as a treatment for Covid-19. Photo / Getty Images
There has been no clinical trial proving hydroxychloroquine as a treatment for Covid-19. Photo / Getty Images
The antimalarial drug used by Donald Trump as a prophylactic for Covid-19 has been linked to a significant increase in the risk of coronavirus patients dying in hospital, according to the largest study of its kind.
The study of 96,000 patients - published in The Lancet yesterday - found those given hydroxychloroquine had a 34 per cent increase in risk of death and a 137 per cent increased risk of serious heart arrhythmia.
In those given hydroxychloroquine and an antibiotic - the combination of treatment endorsed by Trump - there was a 45 per cent increased risk of death and a 411 per cent increased risk of serious heart arrhythmia.
Chloroquine, a closely related drug, had a 37 per cent increased risk of death and a 256 per cent increased risk of serious heart arrhythmia.
There has been no clinical trial proving hydroxychloroquine as a treatment for Covid-19. Photo / Getty Images
The US president caused alarm this week after he revealed he was taking hydroxychloroquine despite health officials' fears over its side effects, asking: "What do you have to lose?"
Trump first promoted the use of the drug as a coronavirus treatment in March, saying it could be a "game changer in the history of medicine".
He prompted a storm of criticism on Monday when he said he had been taking the drug for about a week and a half as a preventive measure, with the approval of his White House doctor.
"All I can tell you is so far I seem to be okay," Trump said, adding: "I get a lot of tremendously positive news on the hydroxy."
Demand for the antimalarial drug surged in the US after Trump first promoted it, with retail sales in March double what they were the previous year, according to analysis from IQVIA, a market research firm.
The Lancet study, conducted by Professor Mandeep Mehra of Harvard Medical School, along with professors from three other institutions, looked at more than 96,000 coronavirus patients who had been admitted to hospitals.
The authors could not confirm if taking the drug resulted in any benefit to Covid-19 patients, while the drug "was associated with decreased in-hospital survival".
Mehra, the study's lead author, said that "randomised trials" were essential to confirm the effects of hydroxychloroquine on coronavirus patients, but added: "In the meantime, we suggest these drugs should not be used as treatments for Covid-19 outside of clinical trials."
Hydroxychloroquine has been approved for use as an antimalarial drug for several decades, but there has been no expansive clinical trial proving its efficacy as a treatment for Covid-19.
Concerns raised in other recent studies of hydroxychloroquine led the US Food and Drug Administration to issue a safety warning about its use as a treatment for coronavirus last month, warning that it could cause dangerous heart problems.
The latest research offers a retrospective analysis of medical records rather than the results of a controlled study, which is the gold standard for medicine, but The Lancet study represents the largest analysis to date of the drug's effect on patients with Covid-19.
Professor Stephen Evans, from the London School of Hygiene and Tropical Medicine, said more research was needed, but added: "It is clear that the drugs should not be given for treatment of Covid-19 other than in the context of a randomised trial.
"It might even be said that to go on giving them other than in a trial is unethical, given this evidence that is not yet contradicted by other available evidence."
The researchers looked at data from 671 hospitals across six continents, where 14,888 patients were given either hydroxychloroquine or chloroquine, with or without macrolide antibiotics, and 81,144 patients were not on any of the treatment regimens.
Earlier this week it was announced that a trial to see whether the drugs could prevent Covid-19 had begun in Brighton and Oxford.
Chloroquine, hydroxychloroquine or a placebo will be given to more than 40,000 healthcare workers from Europe, Africa, Asia and South America.
