A drug supported and even taken by United States President Donald Trump as a potential weapon against the new coronavirus simply doesn't seem to work, another major study finds.
READ MORE | Covid-19: Amid caution over use of hydroxychloroquine, experts warn of possible irreversible blindness
In fact, hydroxychloroquine, as well as a related medicine, chloroquine, may even raise the risk for death and serious heart rhythm disorders in people who use it, an international team of researchers reported.
The two drugs are approved to help treat illnesses such as malaria and lupus. Early on in the Covid-19 pandemic, Trump labeled the drugs potential "game changers" against the disease, despite little good evidence supporting such claims. Google searches by Americans looking for the medicines surged after his endorsement.
And last Monday, Trump told reporters he'd been taking hydroxychloroquine for about a week and a half in an effort to help prevent infection or illness with SARS-CoV-2, the new coronavirus. He said he was taking the drug with the approval of the White House physician.
However, the new research, published May 22 in The Lancet, is the latest in a long line of studies suggesting that the drug is useless against the new coronavirus and Covid-19. And its authors say it may offer the most definitive proof yet.
"This is the first large scale study to find statistically robust evidence that treatment with chloroquine or hydroxychloroquine does not benefit patients with Covid-19," said lead author Dr Mandeep Mehra, executive director of the Center for Advanced Heart Disease at Brigham and Women's Hospital in Boston.
"Instead, our findings suggest it may be associated with an increased risk of serious heart problems and increased risk of death," he said in a journal news release.
The researchers said their observational study findings suggest that the use of the two drugs in Covid-19 patients should be restricted to clinical trials until there's proof from "gold standard" randomized clinical trials that the medications are, in fact, safe and effective.
Mehra's group analysed data from nearly 15 000 hospitalised Covid-19 patients who were given hydroxychloroquine or chloroquine, with or without the antibiotics azithromycin or clarithromycin, and a control group of about 81 000 hospitalised patients who didn't receive the drugs.
The patients were admitted to 671 hospitals between December 20 and April 14, and all had either been discharged or had died by April 21.
The death rate in the control group, which did not receive either hydroxychloroquine or chloroquine, was 9.3%, the Boston team reported.
That's far lower than the 16.4% death rate for the group that received chloroquine alone, or the 18% death rate for those patients who received hydroxychloroquine alone.
Randomised clinical trials essential
Adding antibiotics to the mix didn't help, either: For those receiving chloroquine and an antibiotic the death rate was 22.2%, and it was 23.8% for those who got hydroxychloroquine and an antibiotic, the researchers said.
Even though other factors - including age, obesity and pre-existing health conditions such as heart disease, lung disease and diabetes - might have played a role in the differences in death rates, hydroxychloroquine/chloroquine was still associated with an increased risk of death, the researchers concluded.
As well, serious heart rhythm problems were more common in patients who received either of the four treatment regimens, Mehra's group added.
The highest rate (8%) was among patients given hydroxychloroquine and an antibiotic, compared with 0.3% of patients in the control group.
After accounting for other factors, the researchers calculated that this drug combination was associated with a more than fivefold higher risk of serious heart rhythm problems.
"Randomised clinical trials are essential to confirm any harms or benefits associated with these agents," Mehra said. "In the meantime, we suggest these drugs should not be used as treatments for Covid-19 outside of clinical trials."
Other studies concur
Prior studies have concluded much the same.
For example, one US study published in late April found the death rate for people with Covid-19 who took hydroxychloroquine on top of usual care was actually higher than those who didn't - 28% vs. 11%, respectively.
Soon after, the US Food and Drug Administration issued a statement that "hydroxychloroquine and chloroquine have not been shown to be safe and effective for treating or preventing Covid-19."
The FDA also warned that "hydroxychloroquine and chloroquine can cause abnormal heart rhythms".
On May 8, New York City physicians reporting in the New England Journal of Medicine tracked outcomes for nearly 1 400 patients with severe Covid-19. Those who received hydroxychloroquine fared no better than those who did not.
And now this latest "well-conducted observational study adds to preliminary reports suggesting that chloroquine, hydroxychloroquine, alone or with azithromycin, is not useful and may be harmful in hospitalised Covid-19 patients", Dr Christian Funck-Brentano, of Sorbonne University in Paris, wrote in a journal commentary accompanying the new study.
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