Q&A: Hydroxychloroquine and Heart Rhythm in SLE

H. Michael Belmont, M.D.

Patients with systemic lupus erythematous (SLE) who take hydroxychloroquine do not have any differences in their corrected QT (QTc) intervals on electrocardiogram (EKG), even if they have chronic kidney disease (CKD), according to researchers reporting at the annual meeting of the American College of Rheumatology on Monday.

In this Q&A, co-author H. Michael Belmont, M.D., of New York University Grossman School of Medicine and co-director of NYU Lupus Center, highlights the findings of this retrospective study.

The study included 90 SLE patients who had taken at least one EKG between March 2012 and May 2020. Eight out of 75 patients who were on hydroxychloroquine had prolonged QTc intervals, and one of the 15 patients not taking the drug had a prolonged QTc interval. No significant difference was found in the mean QTc intervals based on hydroxychloroquine treatment. Meanwhile, the 23 patients with CKD did not have any significant differences in their mean QTc intervals either, whether or not they were taking hydroxychloroquine. Severe prolongation of QTc was rare in all groups and no episodes of serious tachyarrhythmia or torsades de pointes (TdP) (or, twisting of peaks) were reported.

Why was the study conducted?

Despite decades of experience with the use of hydroxychloroquine to treat SLE and rheumatoid arthritis there is little concern for malignant arrhythmia related to antimalarial effects on QTc interval as reports of torsades de points are limited to overdoses. Expanded off label use of hydroxychloroquine during the COVID-19 pandemic on the other hand raised potential concerns for cardiac toxicity although this was in a different population of more elderly patients often with co-morbidities including underlying heart disease which contrasts with, for example, lupus which is principally a disease in women of childbearing age.

Given the benefits of hydroxychloroquine in SLE and recommendation it be used as background medication for all lupus patients we wanted to determine its safety in a cohort of SLE patients managed in a faculty group practice at NYU Langone Health including in those with CKD where high drug levels potentially would have greater effects on the QTc interval.

What were the surprises in the results?

There were no statistically greater QTc intervals in patients with SLE exposed or unexposed to hydroxychloroquine regardless of presence of CKD.

How significant are the findings?

The data is reassuring that clinically consequential effects of hydroxychloroquine on the QTc are unlikely.

What is the current practice and how could the findings possibly change this?

Current practice is to prescribe hydroxychloroquine as background medication to all lupus patients and this study should reassure prescribing providers and patients alike and avoid lack of adherence due to unnecessary concerns regarding cardiac safety.

Moreover, there are no current guideline requiring base line or serial EKGs in hydroxychloroquine treated patients and these data do not support need to obtain an EKG.

What are the takeaway points for clinicians who may be reading this article?

Continue the practice of prescribing hydroxychloroquine without concern for serious effects on QTc.

Do you have anything else to add?

Limitations include the need to study hydroxychloroquine effect on QTc intervals in patients with significant coincidental heart disease, more elderly, severe CKD and/or end-stage renal disease on hemodialysis, and in combination with other drugs that can prolong the QTc interval. Additional studies that will provide more reassurance include performing EKG prospectively before and after starting hydroxychloroquine in lupus patients as well as measuring hydroxychloroquine blood levels and determining if there is a dose response curve between levels and QTc intervals.

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REFERENCE

ABSTRACT: 1844. “Hydroxychloroquine and QTc Prolongation in a Cohort of SLE Patients.” The annual meeting of the American College of Rheumatology.11:00 AM, Monday, Nov. 9, 2020.