Hydroxychloroquine and chloroquine, with or without azithromycin or clarithromycin, offer no benefit in treating patients with COVID-19 and, instead, are associated with ventricular arrhythmias and higher rates of mortality, according to a major new international study.
In the largest observational study of its kind, including close to 100,000 people in 671 hospitals on six continents, investigators compared outcomes in 15,000 patients with COVID-19 treated with hydroxychloroquine and chloroquine alone or in combination with a macrolide with 80,000 control patients with COVID-19 not receiving these agents.
Treatment with any of these medications, either alone or in combination, was associated with increased death during hospitalization; compared with about 10% in control group patients, mortality rates ranged from more than 16% to almost 24% in the treated groups.
Patients treated with hydroxychloroquine plus a macrolide showed the highest rates of serious cardiac arrhythmias, and, even after accounting for demographic factors and comorbidities, this combination was found to be associated with a more than 5-fold increase in the risk of developing a serious arrhythmia while in the hospital.
“In this real-world study, the biggest yet, we looked at 100,000 patients [with COVID-19] across six continents and found not the slightest hint of benefits and only risks, and the data is pretty straightforward,” study coauthor, director of the Heart Center at University Hospital, Zürich, said in an interview. The study was published online May 22 in .
The absence of an effective treatment for COVID-19 has led to the “repurposing” of the antimalarial drug chloroquine and its analogue hydroxychloroquine, which is used for treating autoimmune disease, but this approach is based on anecdotal evidence or open-label randomized trials that have been “largely inconclusive,” the authors wrote.
Additional agents used to treat COVID-19 are second-generation macrolides (or ), in combination with or , “despite limited evidence” and the risk for ventricular arrhythmias, the authors noted.
“Our primary question was whether there was any associated benefits of the use of hydroxychloroquine, chloroquine, or a combined regimen with macrolides in treating COVID-19, and — if there was no benefit — would there be harm?” lead author, MSc, William Harvey Distinguished Chair in Advanced Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, said in an interview.
The investigators used data from a multinational registry comprising 671 hospitals that included patients (n = 96,032; mean age 53.8 years; 46.3% female) who had been hospitalized between Dec. 20, 2019, and April 14, 2020, with confirmed COVID-19 infection.
They also collected data about demographics, underlying comorbidities, and medical history, and medications that patients were taking at baseline.
Patients receiving treatment (n = 14,888) were divided into four groups: those receiving chloroquine alone (n = 1,868), those receiving chloroquine with a macrolide (n = 3,783), those receiving hydroxychloroquine alone (n = 3,016) and those receiving hydroxychloroquine with a macrolide (n = 6,221).
The remaining patients not treated with these regimens (n = 81,144) were regarded as the control group.
Most patients (65.9%) came from North America, followed by Europe (17.39%), Asia (7.9%), Africa (4.6%), South America (3.7%), and Australia (0.6%). Most (66.9%) were white, followed by patients of Asian origin (14.1%), black patients (9.4%), and Hispanic patients (6.2%).
Comorbidities and underlying conditions included obesity, hyperlipidemia, and hypertension in about 30%.