COVID-19: Hydroxychloroquine & QT Prolongation / "COVID Toe" / The Pandemic's Future

By Amy Orciari Herman

Edited by Susan Sadoughi, MD, and André Sofair, MD, MPH

Two observational studies in JAMA Cardiology add to evidence that hydroxychloroquine treatment is associated with prolonged QTc interval in patients with novel coronavirus disease (COVID-19).

The first included a cohort of 90 COVID-19 patients admitted to a Boston hospital, all of whom received hydroxychloroquine, with or without azithromycin. Some 19% who received hydroxychloroquine monotherapy developed prolonged QTc of 500 ms or more; 3% had a change in QTc of 60 ms or more. With hydroxychloroquine plus azithromycin, the rates were 21% and 13%, respectively. One patient with QTc prolongation developed torsades de pointes.

Separately, in a study of 40 COVID-19 patients admitted to a French ICU who received hydroxychloroquine, over 90% experienced increased QTc interval. One third of those who received hydroxychloroquine plus azithromycin developed QTc of 500 ms or more, versus 5% of those who received hydroxychloroquine alone. There were no ventricular arrhythmias.

The authors of the first study note that without a control group, they could not rule out cardiotoxicity from COVID-19 as opposed to hydroxychloroquine and azithromycin. Editorialists, meanwhile, say the findings "underscore the potential risk associated with widespread use" of these treatments in COVID-19. They add, "Understanding whether this risk is worth taking in the absence of evidence of therapeutic efficacy creates a knowledge gap that needs to be addressed."

And in other COVID-19 news:

• "COVID Toe": A New York Times story details the emergence of chilblain-like lesions on the toes as "yet another telltale symptom" of COVID-19, although it has not yet made it onto the CDC's symptom list. Dermatologists in San Francisco and Boston told the Times that their practices are "inundated with" and "completely full of" toes. Most patients with this presentation are younger and have a "benign clinical course," and the lesions go away, experts said.

• The pandemic's future: Researchers with the Center for Infectious Disease Research and Policy (CIDRAP) used data from influenza pandemics to predict the future course of the COVID-19 outbreak. They estimate that the outbreak will likely last 18 to 24 months, and 60%–70% of the population may need to be immune for the pandemic to end. They offer three potential scenarios for future waves of the outbreak and advise leaders to prepare for the worst-case scenario — that is, the current wave is followed by a larger wave in the fall or winter of 2020, with at least one smaller wave in 2021.