Impact of Hydroxychloroquine, on QTC Interval, in Patients with Rheumatologic Diseases

Abstract

Background: Hydroxychloroquine (HCQ) has been historically used for treatment of autoimmune diseases and more recently, it is used for treatment of COVID-19 patients. Using HCQ in COVID-19 patients resulted in corrected QT(QTc) prolongation which has potential to deteriorate into Torsades de Pointes and sudden cardiac death. As it is used chronically by rheumatologic patients so this study was designed to establish effect of HCQ on QTc in rheumatic patients. Methods: A cross sectional comparative study conducted in Rheumatology Department Shaikh Zayed hospital, Lahore. Non-probability consecutive sampling technique was used. Duration of study was 169 days. 45 patients used HCQ for three months and 45 patients did not use HCQ. ECG was done at induction in the study and after three months. Serum calcium, potassium and magnesium were also checked at onset. QTc was calculated by Bazett’s formula. Results: QTc did not raise in 21(46%) patients, in both groups. QTc raised between 1- 50msec in 20(44.4%) and 23(51.1%) patients in HCQ exposed and unexposed patients, respectively. QTc rise more than 50msec in 4(8.88%) and 1(2.2%) patient in HCQ exposed and unexposed patients, respectively (p-value=0.344). The QTc change is associated with heart rate showing 75.0% chances of increased QTc among those with increased heart rate. Conclusion: HCQ did not increase QTc interval in 46% study. 8.88% of HCQ exposed population and 2.22% of HCQ unexposed population had significant change in QTc. However, no adverse cardiac events were observed in study duration