Prevalence and risk factors for prolonged QT interval and QT dispersion in patients with type 2 diabetes.
OBJECTIVE
Prolonged QT interval is associated with cardiac arrhythmias and sudden death. The present study determined the prevalence of prolonged QT interval and QT dispersion and defined their clinical and metabolic predictors in patients with type 2 diabetes.


METHODS
Cross-sectional study included 501 patients with type 2 diabetes. A standard 12-lead electrocardiogram was recorded. QT corrected for heart rate (QTc) >440 ms and QT dispersion (QTd) >80 ms were considered abnormally prolonged. QTc ≥ 500 ms was considered a high-risk QTc prolongation. Demographic, clinical and laboratory data were collected. Independent risk factors for prolonged QTc and QTd were assessed using logistic regression analysis.


RESULTS
Prevalence of QTc > 440 ms and QTd > 80 ms were 44.1 and 3.6 %, respectively. Prevalence of high-risk QTc (≥500 ms) was 2 % only. Independent risk factors for QTc prolongation >440 ms were mean blood glucose (β = 2.192, p < 0.001), treatment with sulphonylurea (β = 5.198, p = 0.027), female gender (β = 8.844, p < 0.001), and coronary heart disease (β = 8.636, p = 0.001). Independent risk factors for QTc ≥ 500 ms were coronary heart disease (β = 4.134, p < 0.001) and mean blood glucose level (β = 1.735, p < 0.001). The independent risk factor for prolonged QTd was only coronary heart disease (β = 5.354, p < 0.001).


CONCLUSIONS
Although the prevalence of prolonged QTc > 440 ms is significant, the prevalence of high-risk QTc (≥500 ms) and QTd > 80 ms is very low in patients with type 2 diabetes. Hyperglycaemia and coronary heart disease are strong predictors of high-risk QTc.
Department of Cardiology, Specialist Hospital Merkur, Bulevar Srpskih Ratnika 18, 36210, Vrnjacka Banja, Serbia. ninkov@sbb.rs.
Vladan M
VM
Ninkovic
Clinical Centre, Kragujevac, Serbia.|Medical School, University of Kragujevac, Kragujevac, Serbia.
Srdjan M
SM
Ninkovic
Clinical Centre, Kragujevac, Serbia.|Medical School, University of Kragujevac, Kragujevac, Serbia.
Vanja
V
Miloradovic
Department of Cardiology, Specialist Hospital Merkur, Bulevar Srpskih Ratnika 18, 36210, Vrnjacka Banja, Serbia.
Dejan
D
Stanojevic
Department of Cardiology, Specialist Hospital Merkur, Bulevar Srpskih Ratnika 18, 36210, Vrnjacka Banja, Serbia.
Marijana
M
Babic
Cardiology Department, Clinical Centre of Serbia, Medical School, University of Belgrade, Belgrade, Serbia.
Vojislav
V
Giga
Cardiology Department, Clinical Centre of Serbia, Medical School, University of Belgrade, Belgrade, Serbia.
Milan
M
Dobric
Institute of Cellular Medicine, Faculty of Medical Sciences, Medical School, Newcastle University, Framlington Place, William Leech B., NE2 4HH, Newcastle upon Tyne, UK.|Research Councils UK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK.
Michael I
MI
Trenell
Cardiology Department, Clinical Centre of Serbia, Medical School, University of Belgrade, Belgrade, Serbia.
Nebojsa
N
Lalic
Cardiology Department, Clinical Centre of Serbia, Medical School, University of Belgrade, Belgrade, Serbia.
Petar M
PM
Seferovic
Institute of Cellular Medicine, Faculty of Medical Sciences, Medical School, Newcastle University, Framlington Place, William Leech B., NE2 4HH, Newcastle upon Tyne, UK. djordje.jakovljevic@newcastle.ac.uk.|Research Councils UK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK. djordje.jakovljevic@newcastle.ac.uk.|Clinical Research Facility, Royal Victoria Infirmary, Newcastle upon Tyne, UK. djordje.jakovljevic@newcastle.ac.uk.
Djordje G
DG
Jakovljevic
D000368:Aged; D003327:Coronary Disease / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012737:Sex Factors
ECG; QT dispersion; QT interval; Type 2 diabetes