Most people, myself included, had never heard of the drug hydroxychloroquine until President Trump started claiming it might be a ‘game changer’ in the treatment of COVID-19. Hydroxychloroquine is used to treat malaria, lupus, and rheumatoid arthritis, although its mechanism of action isn’t fully understood. While doctors and scientists across the world are scrambling to try to find better ways to treat COVID-19 and decrease the number of deaths, it is important to make sure we only use treatments that work and don’t cause inadvertent harm.
What is the Evidence that Hydroxychloroquine is Effective in Treating COVID-19?
In cells in a test tube, hydroxychloroquine has anti-viral activity and inhibits the replication of the SARS-CoV-2 virus that causes COVID-19. While that is encouraging, many drugs are effective in killing viruses in isolated cells and then fail to provide clinically relevant results in people. A small trial in France claimed to find a huge improvement in COVID-19 patients treated with both hydroxychloroquine and the antibiotic drug Azithromycin. However, that trial did not measure patient clinical outcomes, included a very small number of patients, and for some reason did not include the results from 6 of the 26 hydroxychloroquine-treated patients, 3 of whom entered the ICU and 1 who died. Including those 4 patients with negative outcomes would have almost certainly eliminated any significant improvement with treatment (more comprehensive critique of this paper by Elisabeth Bik). Another small trial in China found some improvement in clinical outcome with hydroxychloroquine treatment, but appears to be too underpowered to be sure that the effect is real and the study has yet to undergo peer review.
What Type of Evidence Would be Convincing that Hydroxychloroquine is Effective in Treating COVID-19?
The gold standard in medical science is a double blind, placebo controlled study. In these studies, both the doctors and patients don’t know whether the patient is receiving the drug being tested or a placebo (inactive drug like a sugar pill). Participants are randomly assigned into one of the two groups and there shouldn’t be any difference between the two groups, like one group including more older patients that are at higher risk. You would then want to see whether patients in the hydroxychloroquine group had better clinical outcomes like less severe disease and fewer deaths. NYU’s Medical School and others are currently conducting these type of trials to test the efficacy of hydroxychloroquine in a more rigorous way.
Isn’t it Worth Treating COVID-19 with Hydroxychloroquine if There is a Chance it Can Work?
The short answer is no. Every treatment will have potential side effects and could actually cause harm. Hydroxychloroquine’s side effects include lengthening the QT interval of the heart which can lead to heart arrhythmias which are dangerous and can lead the heart to stop pumping blood. Azithromycin also elongates the QT interval and the combination of the two drugs is even more dangerous. If these drugs work in treating COVID-19, those side effects may be worth the benefit of treating COVID-19. There have also been reports of people being poisoned or dying from self medicating with the hydroxychloroquine found in aquarium cleaners.
The other issue in this particular case is the unproven promise of hydroxychloroquine to treat COVID-19 is leading to hoarding and shortages. This means people that need hydroxychloroquine to treat lupus or other diseases are having trouble finding the drugs they need to stay healthy.
Bottom Line: Hydroxychloroquine may be beneficial in the treatment of COVID-19, but we need to see the results of ongoing larger, properly designed clinical trials before using it to treat COVID-19 patients.