Background: Chloroquine was promoted as a COVID-19 therapeutic early in the pandemic. Most countries have since discontinued the use of chloroquine due to lack of evidence of any benefit and the risk of severe adverse events. The primary aim of this study was to examine if administering chloroquine during COVID-19 imposed an increased risk of ischemic heart injury or heart failure.
Methods: Medical records, laboratory findings, and electrocardiograms of patients with COVID-19 who were treated with 500 mg chloroquine phosphate daily and controls not treated with chloroquine were reviewed retrospectively. Controls were matched in age and severity of disease.
Results: We included 20 patients receiving chloroquine (500 mg twice daily) for an average of five days, and 40 controls. The groups were comparable regarding demographics and biochemical analyses including C-reactive protein, thrombocytes, and creatinine. There were no statistically significant differences in cardiac biomarkers or in electrocardiograms. Median troponin T was 10,8 ng/L in the study group and 17.9 ng/L in the control group, whereas median NT-proBNP was 399 ng/L in patients receiving chloroquine and 349 ng/L in the controls.
Conclusions: We found no increased risk of ischemic heart injury or heart failure as a result of administering chloroquine. However, the use of chloroquine to treat COVID-19 outside of clinical trials is not recommended, considering the lack of evidence of its effectiveness, as well as the elevated risk of fatal arrythmias.