The World Health Organisation (WHO) has decided to temporarily discontinue treatment with hydroxychloroquine against coronavirus in the Solidarity study, after some studies have highlighted its high mortality rate.

This was reported by WHO director general Tedros Adhanom Ghebreyesus, referring to a large study published last Friday in the Lancet, in which the authors showed how treatment with the antimalarial drug chloroquine and its analogue, hydroxychloroquine, used to treat autoimmune diseases such as lupus and arthritis, offer no benefit for patients with Covid-19. In fact, it could increase mortality and cause further complications, such as severe cardiac arrhythmia.

(photo: George Frey / AFP via Getty Images)

To understand this, the researchers reviewed the data of about 15 thousand patients hospitalised between 20 December 2019 and 14 April 2020, who were administered one of these two drugs , alone or in combination with macrolide antibiotics. Comparing them with the data from the control group (about 81 thousand patients), the researchers observed that at the end of the study period, all four treatments (chloroquine or hydroxychloroquine alone, or in combination with a microlide) were associated with a higher mortality rate than the control group.

Of the patients treated with chloroquine or hydroxychloroquine alone, about one in six died, and when these two drugs were used in combination with a macrolide, the mortality rate went up further: one in five patients for chloroquine and almost one out of four for hydroxychloroquine. In addition, the researchers observed that severe cardiac arrhythmia were more common in patients receiving one of four treatment regimens. The greatest increase, the authors point out, was observed in the hydroxychloroquine group in combination with the antibiotic, in which 8% of patients developed cardiac arrhythmia compared to 0.3% of patients in the control group.

Although this is an observational study (i.e. it does not demonstrate a cause-effect relationship but only an association), the results showed that the use of these two drugs, alone or in combination with antibiotics, is associated with a plus high risk of mortality and serious complications, especially for heart health. These treatment regimens, the authors suggest, should therefore not be used to treat Covid-19 outside trials, until results of randomized clinical trials are available to confirm its safety and efficacy against the new coronavirus.

“This is the first large-scale study to find statistically solid evidence that treatment with chloroquine or hydroxychloroquine does not benefit patients with Covid-19,” explains study author Mandeep R. Mehra of Brigham and Women’s. Boston Hospital. Indeed, our results suggest that it may be associated with an increased risk of serious heart problems and an increased risk of death. Randomised clinical trials are essential to confirm any harm or benefit associated with these agents. In the meantime, we suggest that these drugs should not be used as treatments for Covid-19 outside of clinical trials.”