QT dispersion: comparison between participants with Type 1 and 2 diabetes and association with microalbuminuria in diabetes.
OBJECTIVE
The interlead variation of QT duration in surface electrocardiogram [ECG; QT dispersion (QTd)] has been shown to predict mortality in both diabetic and general population. Diabetic cardiac autonomic neuropathy (CAN) is a common complication of diabetes, and it is also associated with worse prognosis among the diabetic population. In this study, we investigated the association between QTd duration and CAN, as well as other complications of diabetes in participants with Types 1 and 2 diabetes.


METHODS
A total of 184 patients with either Type 1 (n=63) or 2 (n=121) diabetes, as well as 100 control participants, matched for age and sex with the diabetic individuals, were studied. QT and RR intervals were measured on 12 leads of resting ECG tracing. QTd was calculated semiautomatically using a computer program as the difference between the maximum and the minimum QT in any of the 12 leads. CAN was diagnosed when two out of the four classical tests were abnormal.


RESULTS
QTd was not significantly different between controls and patients with either Type 1 or 2 diabetes. Age-adjusted QTd intervals were not significantly different between patients with Types 1 and 2 diabetes (P=.86). For both types of diabetes, no significant differences were found in QTd between patients with and without CAN. Multivariable linear regression analysis, after adjustment for a number of confounding factors, demonstrated a positive association between QTd and duration of diabetes (P=.02) in the group of the patients with Type 1 diabetes. In those with Type 2 diabetes, QTd was associated with age (P=.006) and presence of microalbuminuria (P=.001). In addition, no significant association was found with retinopathy or blood pressure levels.


CONCLUSIONS
Age-adjusted QTd interval was not different between patients with Types 1 and 2 diabetes. CAN is not associated with QTd interval in both types of diabetes. Furthermore, microalbuminuria was found to be the strongest predictor of QTd in patients with Type 2 diabetes. Because long QTd interval predicts cardiac mortality in participants with diabetes, it is suggested that it may be a useful adjuvant index in the evaluation of cardiovascular risk in participants with Type 2 diabetes and microalbuminuria.
Psallas
Michael
M
1st Department of Propaedeutic Medicine, Athens University Medical School, Laiko Hospital, Athens, Greece.
Tentolouris
Nicholas
N
Papadogiannis
Dimitrios
D
Doulgerakis
Dimitrios
D
Kokkinos
Alexandros
A
Cokkinos
Dennis V
DV
Katsilambros
Nicholas
N
D000328:Adult; D000419:Albuminuria / Q000150:complications*; D001786:Blood Glucose; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000401:mortality / Q000503:physiopathology*; D003930:Diabetic Retinopathy; D004562:Electrocardiography; D005260:Female; D006442:Glycated Hemoglobin; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis
D001786:Blood Glucose; D006442:Glycated Hemoglobin