Study finds hydroxychloroquine linked to higher death rate in Covid-19 patients

The study evaluated 96,000 Covid-19 patients in 671 hospitals worldwide. Copyright 2020 The Associated Press. All Rights Reserved.

A study by the University Hospital of Zurich and Harvard Medical School finds the controversial antimalarial drugs, hydroxychloroquine and a similar drug chloroquine, show no benefit against Covid-19.

According to the studyExternal link published on Friday in the Lancet, hospitalised patients taking a regimen of the antimalarial drugs had a higher mortality rate. Patients treated with one of the drugs had a mortality rate of 11.1%, compared with 9.3% for a control sample.

The study, which was led by researchers at Harvard Medical School and the University Hospital of Zurich, evaluated 96,000 Covid-19 patients in 671 hospitals worldwide. About 15,000 of them were treated with one of the antimalarial drugs with or without antibiotics (macrolides such as azithromycin and clarithromycin) at the onset of the disease.

The researchers also observed a four-fold increased risk of cardiac arrhythmia. Some 4-8% of patients treated with one of the antimalarial drugs experienced a new heart arrhythmia, compared to 0.3% for those who were not taking such treatment.

There is “no scientific evidence” of the effectiveness of hydroxychloroquine and chloroquine, said Frank Ruschitzka, head of the Department of Cardiology at the University Hospital of Zurich in a statementExternal link.

“Hydroxychloroquine and chloroquine should therefore no longer be used for Covid-19 before we have the results of further, currently ongoing randomised clinical studies.”

The antimalarial drugs have been surrounded by controversy after enthusiastic remarks by US President Donald Trump earlier this year that left some epidemiologists uneasy given the well-known risks of the drugs particularly for people with heart conditions.

Last week, President Trump indicated that he has been taking hydroxychloroquine as a preventative measure. The US Food and Drug Administration (FDA) granted the drug emergency use authorization earlier this year but European authorities have been less enthusiastic about the drug.

Some of the excitement and hope stemmed from some pre-clinical studies as well as anecdotal evidence that it improved patents’ recovery.

In Switzerland, 17 hospitals are currently participating in a World Health Organization (WHO) solidarity study to test the effectiveness of hydroxychloroquine.