Risk of QTc Prolongation in a Cohort of Opioid- Dependent HIV-Infected Patients on Methadone Maintenance Therapy

Background. Concern regarding the QTc interval in human immunodeficiency virus (HIV)–infected patients has been growing in recent years, and cases of prolonged QTc interval and torsades de pointes have been described in HIV-infected patients on methadone therapy. This study aimed to determine the prevalence and factors associated with long QTc interval in a cohort of opioid-dependent HIV-infected patients on methadone maintenance therapy. Methods. A cross-sectional study was conducted in opioid-dependent HIV-infected patients on methadone main-tenance therapy at a drug abuse outpatient center. Patients with any cardiac disease, drug-positive urine test, electrolyte abnormalities, and changes in their antiretroviral therapy (ART) or methadone doses in the last 2 months were exclud-ed. Heart rate and QT interval in lead II were measured using the Bazett formula. Results. Ninety-one patients were included: 58 (63.7%) were men with a median age of 44.5 years and 68 of 91 (74.7%) were on ART. Median methadone dose was 70 mg/day (range 15–250 mg/day) and mean QTc interval was 438 ± 34 ms. Prolonged QTc interval (>450 ms) was documented in 33 of 91(36.3%) patients, and 3 of 91 (3.2%) had QTc>500 ms. On multiple linear regression analysis, methadone doses (P =.005), chronic hepatitis C–induced cirrho-sis (P =.008), and being ART-naive (P =.036) were predictive of prolonged QTc. Conclusions. The prevalence of prolonged QTc interval in opioid-dependent HIV-infected patients on metha-done maintenance therapy is high. Risk factors for prolongation of the QTc interval are chronic hepatitis C–induce