Racial susceptibility for QT prolongation in acute drug overdoses

Background and Purpose QT prolongation independently predicts adverse cardiovascular events in suspected poisoning. We aimed to evaluate the association between race and drug-induced QT prolongation for patients with acute overdose. Methods This was a cross-sectional observational study at two urban teaching hospitals. Consecutive adult ED patients with acute drug overdose were prospectively enrolled over a two year period. The primary outcome, long-QT, was defined using standard criteria: QTc > 470 ms in females and > 460 ms in males. The association between race and drug-induced QT prolongation was tested, considering several confounding variables. Results In 472 patients analyzed (46% female, mean age 42.3), QT prolongation occurred in 12.7%. Blacks had two-fold increased odds of drug-induced QT prolongation (OR 2.01, CI 1.03-3.91) and Hispanics had 48% decreased odds of drug-induced QT prolongation (OR 0.52, CI 0.29-0.94). Conclusions We found significant racial susceptibility to drug-induced QT prolongation in this large urban study of acute overdoses.