Large study finds hydroxychloroquine Covid-19 treatments linked to greater risk of death and heart arrhythmia

A pharmacy technician holds a hydroxychloroquine pill at a pharmacy in Provo, Utah, on May 20. George Frey/AFP/Getty Images

Seriously ill Covid-19 patients who were treated with hydroxychloroquine and chloroquine were more likely to die or develop dangerous heart arrhythmias, according to a large observational study published Friday in the medical journal The Lancet.

Researchers analyzed data from more than 96,000 patients with confirmed Covid-19 from 671 hospitals. All were hospitalized from late December to mid-April, and had died or been discharged by April 21.

Just below 15,000 patients were treated with the antimalarial drugs hydroxychloroquine or chloroquine, or one of those drugs combined with an antibiotic.

All four of those treatments were linked with a higher risk of dying in the hospital. About 1 in 11 patients in the control group died in the hospital. About 1 in 6 patients treated with chloroquine or hydroxychloroquine alone died in the hospital. About 1 in 5 treated with chloroquine and an antibiotic died and almost 1 in 4 treated with hydroxychloroquine and an antibiotic died.

Researchers also found that serious cardiac arrhythmias were more common among patients receiving any of the four treatments. The largest increase was among the group treated with hydroxychloroquine and an antibiotic; 8% of those patients developed a heart arrhythmia, compared with 0.3% of patients in the control group.

“Previous small-scale studies have failed to identify robust evidence of a benefit and larger, randomised controlled trials are not yet completed,” study co-author Dr. Frank Ruschitzka, director of the Heart Center at University Hospital Zurich, said in a statement. “However, we now know from our study that the chance that these medications improve outcomes in COVID-19 is quite low.”

Some context: The drug, hydroxychloroquine, has been around for decades but was thrust into the spotlight this spring when Trump began mentioning its name dozens of times during coronavirus briefings. While it had not been approved for this use, and still hasn't, he urged Americans to "try it."