New York, May 23 (IANS) A significant observational study led by Professor Mandeep R. Mehra, executive director of the Brigham and Women's Hospital Center for Advanced Heart Disease in Boston, has claimed that treatment with antimalarial drug chloroquine or hydroxychloroquine (taken with or without antibiotics azithromycin or clarithromycin) offers no benefit for patients with Covid-19.
The study, published in the prestigious journal The Lancet, comes after US President Donald Trump said he is taking hydroxychloroquine to ward off coronavirus, even though health officials have warned it may be unsafe.
"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," said Mehra.
"Instead, our findings suggest it may be associated with an increased risk of serious heart problems and increased risk of death,a he warned.
The study analysed data from nearly 15,000 patients with Covid-19, receiving a combination of any of the four drug regimens and 81,000 controls.
Treatment with these medications among patients with COVID-19, either alone or in combination with macrolide antibiotics, was linked to an increased risk of serious heart rhythm complications in these patients.
Researchers suggest these treatment regimens should not be used to treat COVID-19 outside of clinical trials until results from randomised clinical trials are available to confirm the safety and efficacy of these medications for COVID-19 patients.
"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," said Mehra.
Chloroquine is an antimalarial drug and its analogue, hydroxychloroquine, is used to treat autoimmune diseases including lupus and arthritis.
Both drugs have a good safety profile as treatments for those specific conditions, and the findings do not imply patients should stop taking these drugs if they are prescribed for approved conditions.
In the study, researchers analysed data from 96,032 patients hospitalised between December 20 2019 and April 14 2020 with laboratory confirmed SARS-CoV-2 infection from 671 hospitals.
All of the patients included in the study had either been discharged or had died by April 21.
The team compared outcomes from patients treated with chloroquine alone (1,868), hydroxychloroquine alone (3,016), chloroquine in combination with a macrolide (3,783) or hydroxychloroquine with a macrolide (6,221). Patients from these four groups were compared with the remaining control group of 81,144 patients.
At the end of the study period, around one in 11 patients in the control group had died in hospital.
All four of the treatments were associated with a higher risk of dying in hospital.
The team 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 receiving either of the four treatment regimens.
The biggest increase was seen in the group treated with hydroxychloroquine in combination with a macrolide, where 8 per cent of patients developed a heart arrhythmia compared with 0.3 per cent patients in the control group (226/81144).
Several countries have advocated use of chloroquine and hydroxychloroquine, either alone or in combination, as potential treatments for Covid-19.
"Justification for repurposing these medicines in this way is based on a small number of anecdotal experiences that suggest they may have ," said Professor Dr Frank Ruschitzka, Director of the Heart Center at University Hospital Zurich who also co-authored the study.
"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," he elaborated.