Prolonged QTc Interval in Nigerian Children with Sickle Cell Anemia

Prolonged QTc interval, a risk factor for ventricular arrhythmia, occurs in sickle cell anemia. The aim of this study was to determine the risk of prolonged QTc interval and its relationship with vaso-occlusive painful crises (VOCs) and follow-up steady-state in the same children with sickle cell anemia. This prospective cohort study enrolled 38 subjects, aged 5-17 years. History of bone pain and examination were obtained during VOC and steady-state. Assessment of QTc interval was with 12-lead electrocardiography. The QTc interval value >0.440 seconds was taken as prolonged. Median (interquartile range) of QTc interval was higher during VOC [0.447 (0.438-0.459) seconds] than during steady-state [0.435 (0.417-0.440) seconds]. Risk of prolonged QTc interval was higher during VOC (68.4%) than in steady-state (21.1%) with relative risk of 3.250 [95% confidence interval (CI) = 1.692-6.241]. Prolonged QTc interval was likely to occur [area under curve (AUC) = 0.759, p<0.001] during VOC with 68.4% sensitivity, 78.9% specificity and at cutoff point of 0.441 seconds. Prolonged QTc interval negatively correlated with packed cell volume (PCV) during VOC [r(s) (36) = -0.14, p = 0.387]. Binary logistics of the combined effect of PCV and gender on QTc interval showed that during VOC, males were more likely to have prolonged QTc [odds ratio (OR): 1.337 (95% CI: 0.327-5.464; p = 0.686]. Children with sickle cell anemia, particularly males, were three-times more likely to have prolonged QTc interval during VOC when QTc interval was >0.441 seconds. Routine electrocardiography may help to identify those with QTc intervals above this threshold for prompt cardiac-oriented management.