By Pat Anson, PNN Editor

A large international study on the use of hydroxychloroquine and chloroquine for treating COVID-19 has found the antimalarial drugs offer no benefit for hospitalized coronavirus patients and appear to significantly raise the risk of death, particularly when taken with antibiotics.

The study, published in the peer-reviewed journal The Lancet, looked at data from nearly 15,000 patients with COVID-19 who received hydroxychloroquine or chloroquine, with or without the use of antibiotics. They were compared to a control group of over 81,000 patients who did not take the drugs. The study included patients being treated at 671 hospitals in North America, Europe, Asia, Africa, South America and Australia.

(Update: On June 4, The Lancet retracted this study after the authors said were unable to complete an independent audit of their research and concluded they “can no longer vouch for the veracity of the primary data sources.”)

“We found no evidence of benefit of hydroxychloroquine or chloroquine when used either alone or with a macrolide (antibiotic),” researchers said. “Our study included a large number of patients across multiple geographic regions and provides the most robust real-world evidence to date on the usefulness of these treatment regimens. Although observational studies cannot fully account for unmeasured confounding factors, our findings suggest not only an absence of therapeutic benefit but also potential harm.”

The study found that 9.3% of patients in the control group died in the hospital. Of those treated with chloroquine or hydroxychloroquine alone, 16.4% died. The outcomes were even worse for patients who used chloroquine with an antibiotic (22.2%) or hydroxychloroquine with an antibiotic (23.8%).

Researchers also found that serious cardiac arrhythmias, which cause the lower chamber of the heart to beat rapidly and irregularly, were more common in the groups that took hydroxychloroquine or chloroquine.

“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. Instead, our findings suggest it may be associated with an increased risk of serious heart problems and increased risk of death,” said lead author Mandeep Mehra, MD, Executive Director of the Brigham and Women’s Hospital Center for Advanced Heart Disease.

“Randomised clinical trials are essential to confirm any harms or benefits associated with these agents. In the meantime, we suggest these drugs should not be used as treatments for COVID-19 outside of clinical trials.”

President Trump disclosed this week that he has been taking hydroxychloroquine as a preventative treatment for COVID-19, even though there is only anecdotal evidence the drug may work against the virus. The president said he was prescribed the drug by his physician after two White House staff members were diagnosed with the virus. Trump said he would only take hydroxychloroquine for about two weeks.

The Food and Drug Administration has said hydroxychloroquine or chloroquine should not be used as frontline treatments for COVID-19 outside of hospitals and clinical trials.

The FDA has only approved chloroquine to treat malaria and hydroxychloquine as a treatment for lupus and rheumatoid arthritis. Both drugs have good safety profiles for those conditions.

Chloroquine and hydroxychloquine have been shown to have antiviral effects in laboratory tests, which has sparked interest in their use as potential treatments for COVID-19. Some countries have been stockpiling the drugs. In March, the FDA added hydroxychloquine and chloroquine to its list of drug shortages. Chloroquine was recently taken off the list.

“Several countries have advocated use of chloroquine and hydroxychloroquine, either alone or in combination, as potential treatments for COVID-19,” said co-author Frank Ruschitzka, MD, Director of the Heart Center at University Hospital Zurich.

“Justification for repurposing these medicines in this way is based on a small number of anecdotal experiences that suggest they may have beneficial effects for people infected with the SARS-CoV-2 virus. However, previous small-scale studies have failed to identify robust evidence of a benefit and larger, randomised controlled trials are not yet completed. However, we now know from our study that the chance that these medications improve outcomes in COVID-19 is quite low.”

In addition to their findings on chloroquine and hydroxychloroquine, researchers also noted that obesity, heart disease, diabetes and smoking raise the risk of death for hospitalized COVID-19 patients. Interestingly, patients being treated with statins or ACE inhibitors for high blood pressure had a lower risk of mortality, suggesting that medications that stabilize the cardiovascular system may be beneficial.