A worldwide observational study with 96,000 hospitalized COVID-19 patients showed that those who were treated with hydroxychloroquine or chloroquine had a higher mortality rate and a particularly increased risk of cardiac arrhythmia.
A research team from the Brigham and Women's Hospital (Harvard Medical School, Boston), in collaboration with the Department of Cardiology at the Heart Center of the Zurich University Hospital (in German: Herzzentrum des Universitätsspitals Zürich), evaluated the results of a worldwide observational study in patients hospitalized for COVID-19.
In particular, patients treated with hydroxychloroquine or chloroquine (with or without macrolide antibiotics) showed a higher risk of life-threatening cardiac arrhythmia.
"Hydroxychloroquine and chloroquine show no benefit in patients hospitalized with Covid-19," said Mandeep R. Mehra, MD, Executive Director of the Center for Advanced Heart Disease, Brigham and Women's Hospital, "The data even indicate an increased risk of death. We also observed a fourfold increase in the number of arrhythmias in COVID-19 patients treated with hydroxychloroquine or chloroquine”, Mehra added.
Prof. Frank Ruschitzka, Head of the Department of Cardiology at the Heart Centre of the University Hospital of Zurich added: "There is no scientific evidence for the efficacy of hydroxychloroquine and chloroquine in Covid-19. On the contrary, we observed severe side effects, especially life-threatening cardiac arrhythmias, especially in Covid-19 patients with heart disease. Hydroxychloroquine and chloroquine should therefore no longer be used in COVID-19 before we have the results of further randomized clinical trials currently underway".
The research team led by Mehra and Ruschitzka conducted the study using the Surgical Outcomes Collaborative Database, an international registry containing anonymized data from 671 hospitals across all continents. The analysis included data from over 96,000 patients hospitalized with COVID-19. Nearly 15,000 of these patients had been treated with the antimalarial drug chloroquine or with hydroxychloroquine with or without antibiotics early after the COVID-19 diagnosis.
The researchers found that 10,698 patients who had received one or other of these drugs died in hospital (11.1%) and that 85,334 survived and were discharged. The team compared this mortality rate with that of a control group, taking age, gender, and risk factors into account. The mortality rate in the control group was 9.3%.
Chloroquine or hydroxychloroquine alone or in combination with a macrolide were therefore associated with an increased risk of death in a hospital with COVID-19. In the therapy groups, between 4% and 8% of patients experienced a new cardiac arrhythmia, compared to 0.3% of patients in the control group.
In conclusion, the authors pointed out that the results of ongoing randomized clinical trials must be awaited before definitive conclusions can be drawn regarding the risk of exposure to chloroquine and hydroxychloroquine.