Systemic lupus erythematosus (SLE) patients using hydroxychloroquine have a markedly lower risk of a type of abnormal heart rhythm called atrial fibrillation than those not being treated with the therapy, according to a retrospective study.
The research, “Association of Hydroxychloroquine Use and Incident Atrial Fibrillation in Systemic Lupus Erythematosus: A Retrospective Study,” was presented at the at the recent 2018 American College of Rheumatology (ACR)/Association for Rheumatology Health Professionals (ARHP) Annual Meeting, held in Chicago.
The antimalarial therapy hydroxychloroquine, a standard treatment in SLE, is frequently used to prevent ventricular arrhythmias — abnormal heart rhythms originating in the heart’s bottom chambers, the ventricles — and recurrent atrial fibrillation, a chaotic and irregular beat in the heart’s two upper chambers, the atria. Atrial fibrillation is more common in SLE patients than in the general population.
The team from Allegheny Health Network and Allegheny General Hospital, in Pittsburgh, Pennsylvania, conducted a retrospective study between December 2014 and May 2017 to evaluate the link between hydroxychloroquine use and incident (newly diagnosed) atrial fibrillation or ventricular arrhythmias in adults with SLE.
Atrial fibrillation and ventricular arrhythmia cases were collected by electronic health record review and confirmed via electrocardiography. Atrial fibrillation events during the first year of observation were considered prevalent and thereby excluded.
Incident ventricular arrhythmias comprised ventricular tachycardia — faster heartbeat than normal — ventricular fibrillation, torsades — a type of ventricular tachycardia — and sudden cardiac death.
The correlation between hydroxychloroquine exposure and atrial fibrillation was assessed after adjusting for confounders, including age, sex, ethnicity, related comorbidities — body mass index, alcohol use, smoking, chronic obstructive pulmonary disease, obstructive sleep apnea, diabetes, hypertension, coronary artery disease, cerebrovascular accident and transient ischemic attack, heart failure, peripheral vascular disease, thyroid disorder, chronic kidney disease, and liver dysfunction — anti-arrhythmic medications such as beta blockers and calcium channel blockers, and autoantibodies (those directed against the body’s own tissues).
Also, subgroup analysis was performed on patients older than 65, given their higher risk for atrial fibrillation.
Of the patients in the study, 934 were hydroxychloroquine users (mean age 52.2 years, 93% women) and 754 were non-users (mean age 56.3 years, 92% women).
During the observation period, five atrial fibrillation events occurred in hydroxychloroquine users and 18 in non-users. Subsequent analyses with adjustment for confounders revealed that the risk for incident atrial fibrillation was 67% lower in hydroxychloroquine users.
Six incident ventricular arrhythmia events — two ventricular tachycardias, three torsades and one sudden cardiac death — occurred in hydroxychloroquine users. There were three — two ventricular tachycardias and one sudden cardiac death — in non-users, which did not represent a statistically significant difference. Also, the risk was not significantly higher in patients older than 65.
“In this exploratory study, [hydroxychloroquine] use was associated with a 67% reduced risk of incident [atrial fibrillation] in SLE,” the scientists said.
They added that given the cardiovascular risk benefits of hydroxychloroquine and the fact that it is a derivative of the anti-arrhythmic medication quinidine, potential confirmation of the findings in larger studies may support “a randomized study of [hydroxychloroquine’s] protective role against [atrial fibrillation] in high-risk patients with SLE.”