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The relation between QTc interval prolongation and diabetic complications. The EURODIAB IDDM Complication Study Group
M Veglio1, M Borra, L K Stevens
1Ospedale Mauriziano, Torino, Italy.
Insights
QT interval prolongation is more common in women with diabetes. This prolonged QT interval is linked to diabetes complications and may increase the risk of sudden cardiac death in diabetic patients.
Area of Science:
- Cardiology
- Endocrinology
- Diabetology
Background:
- QT interval prolongation is more prevalent in diabetic individuals and linked to sudden death, particularly in those with autonomic neuropathy.
- The study investigates the association between QT prolongation and diabetic complications.
Purpose of the Study:
- To evaluate the prevalence of QT interval prolongation and its relationship with diabetic complications in insulin-dependent diabetic patients.
- To explore potential differences in QT prolongation between males and females with diabetes.
Main Methods:
- Analysis of resting ECG tracings from 3250 insulin-dependent diabetic patients across 16 European countries (EURODIAB IDDM Complications Study).
- Measurement of RR and QT intervals, with corrected QT (QTc) calculated using Bazett's formula.
- Statistical analysis to identify associations between QTc duration and demographic, clinical, and complication-related factors.
Main Results:
- Overall prevalence of prolonged QTc was 16% (11% in males, 21% in females).
- QTc duration was independently associated with age, HbA1c, and blood pressure.
- QTc prolongation correlated with ischemic heart disease and nephropathy, more strongly in males. Autonomic neuropathy was linked to higher QTc in males but not females.
- Female patients exhibited longer QTc than males, irrespective of known risk factors.
Conclusions:
- QTc prolongation is a significant finding in insulin-dependent diabetes, with higher prevalence in females.
- Factors like age, HbA1c, blood pressure, and specific complications influence QTc duration.
- The observed longer QTc in diabetic females warrants further investigation, especially concerning cardiac arrhythmia risk.
Abstract:
The prevalence of QT interval prolongation is higher in people with diabetes and its complications. Sudden death has been reported as a common cause of death in insulin-dependent diabetic patients affected by autonomic neuropathy. It has been postulated that QT prolongation predisposes to cardiac arrhythmias and sudden death. In this analysis the prevalence of QT interval prolongation and its relation with diabetic complications were evaluated in the EURODIAB IDDM Complications Study (3250 insulin-dependent diabetic patients attending 31 centres in 16 European countries). Five consecutive RR and QT intervals were measured with a ruler on the V5 lead of the resting ECG tracing and the QT interval corrected for the previous cardiac cycle length was calculated according to the Bazett's formula. The prevalence of an abnormally prolonged corrected QT was 16% in the whole population, 11% in males and 21 % in females (p < 0.001). The mean corrected QT was 0.412 s in males and 0.422 s in females (p < 0.001). Corrected QT duration was independently associated with age, HbA1c and blood pressure. Corrected QT was also correlated with ischaemic heart disease and nephropathy but this relation appeared to be stronger in males than in females. Male patients with neuropathy or impaired heart rate variability or both showed a higher mean adjusted corrected QT compared with male patients without this complication. The relation between corrected QT prolongation and autonomic neuropathy was not observed among females. In conclusion we have shown that corrected QT in insulin-dependent diabetic female patients is longer than in male patients, even in the absence of diabetic complications known to increase the risk of corrected QT prolongation.