Assessment of corrected QT interval in children with type 1 diabetes mellitus

Background Type 1 diabetes mellitus (T1DM) is associated with increased risk for cardiovascular complications. It was reported that children and adolescents with T1DM have a six-fold greater risk for prolongation of the QT interval. QT prolongation has been suggested as an independent marker of increased mortality in patients with T1DM.Objective To study the corrected QT (QTc) interval in children attending the Alexandria University Children’s Hospital with T1DM and its relation to the glycemic control and duration of the disease.Patients and methods The study included 60 children with T1DM (aged 4–15 years) compared with 60 healthy matched children. All children were subjected to thorough history taking and clinical examination. The QT interval was measured on 12-lead resting electrocardiogram and the QTc was calculated using Bazett’s formula, in all cases and controls. The glycosylated hemoglobin (HbA1c%) was measured in all cases and controls.Results One-third of the diabetic children had prolonged QTc interval (≥0.45 s), whereas all controls had normal QTc interval (<0.45 s). The great majority (95%) of the patients with prolonged QTc interval had inadequate glycemic control (HbA1c >7.5%). A significant positive correlation was found between the QTc interval and both the HbA1c% and the duration of diabetes.Conclusion Prolongation of the QTc interval is very prevalent among children with T1DM attending the Alexandria University Children’s Hospital. This is tied to the poor glycemic control and duration of diabetes. Therefore, good glycemic control and follow-up of QTc interval are mandatory to minimize the potential for life-threatening events among our diabetic children.