ANAEMIA PREDICTS PROLONGED QT INTERVAL IN PREDIALYSIS CHRONIC KIDNEY DISEASE PATIENTS

Background. Patients with advanced chronic kidney disease (CKD) have increased cardiovascular mortality of multifactorial aetiology including cardiac arrhythmias. Prolonged QT interval may be responsible for some of the cardiac deaths. This prospective cross sectional study investigated the QTc in predialysis chronic kidney disease patients compared with age and sex matched controls subjects. It also investigated association between QTc and variables that may affect it.Methods. Ninety one patients in CKD stages 3 to 5 and thirty two control subjects matched for age and sex were studied using standard 12-lead electrocardiogram.Results. Fifty four (59.3%) of CKD patients had abnormal QTc defined as QTc ≥0.44. This was observed in all the stages of CKD studied (67% for CKD stage 3, 62% for stage 4 and 58% for stage 5). There was no statistical difference in the frequency of abnormal QTc between the stages of CKD, p = 0.707. All the control subjects had normal QTc with a mean of 0.38±0.02. BMI, SBP, DBP, Hb, and aetiology of CKD correlated with QTc. Only Hb predicted the presence of prolonged QTc in CKD. Conclusion. The QTc interval is significantly prolonged in predialysis CKD patients in this study. This abnormality was present in stages 3 to 5 CKD. This may be a contributing factor to the high cardiovascular mortality in CKD patients. Anaemia was predictive of prolonged QTc in this study. It is reasonable to recommend an ECG as part of the evaluation of all patients with CKD.