Determination of sensitivity and specificity of QT interval in ECG of diabetic patients for ndiagnosis of cardiac autonomic neuropathy

Abstract

one of the important complications of diabetes mellitus that physicians pay less attention to is diabetic autonomic neuropathy(DNA) ,especially cardiac autonomic neuropathy (CAN).this has a poor prognosis and is accompanied by sudden death risk,recently several investigations that were carried out for CAN detection ,suggested that QT-interval prolongation in these patients is an important diagnostic criteria.in this cross-sectional study attempts were made to detect CAN prevalence in 180 non-insulin dependent diabetes mellitus (NIDDM)patients who were between 35-60 years -old.the specificity and sensitivity of the QT-interval was calculated and compared whit the results of other studies.for detection of this dysfunction 53 male and 127 female patients were examined.46 patients (11 males and 35 females) or 25.5% had CAN.92 patients(51.1%) had prolonged QT interval and among 46 patients with CAN ,30 patients (65.2%) had prolonged QT interval.the specificity was 53.7% and sensitivity was 65.2%.the test accuracy was 59.4% that ia far from the minimum acceptable value of 75%.the results reoresent that the test had not enough sensitivity for diagnosis of CAN in diabetic patients.however the study confirmed the high rate for autonomic dysfunction in diabetic patients.