Sex difference in the relationship between insulin resistance and QTc interval in Korean non-diabetic subjects

Shin, Hun Sub; Lee, Won Young; Kim, Sun Woo; Jung, Chan Hee; Lee, Eun Jung; Sung, Ki Chul; Kim, Bum Soo; Kang, Jin Ho; Lee, Man Ho; Park, Jung Ro

Abstract

BACKGROUND: Men with prolonged corrected QT interval (QTc) are at increased risk for cardiovascular mortality and sudden death, even in healthy person. Also prolonged QTc predicts the mortality in diabetic persons. However the relationship between insulin resistance and QTc is not well known in healthy people without diabetes. This study was performed to observe the association between QTc and insulin resistance in Korean non-diabetic subjects.
METHODS
Total 874 subjects (520 men, 354 women, mean age 45.9+/-11.0 years) who underwent medical check-up at health promotion center in Kangbuk Samsung Hospital from January 2002 to May 2002 were included in this study. Age, sex, height, body weight, blood pressure, blood cholesterol, triglyceride, HDL cholesterol, fasting insulin, and fasting glucose levels were measured. QT intervals were corrected with Bazett's formula (QTc=QT/ RR). HOMA (Homeostasis model assessment) were calculated in order to assess the correlations between insulin resistance indices and QTc interval.
RESULTS
The means of QTc intervals were significantly longer in females (417.0+/-24.0 msec) compared to males (402.4+/-22.7 msec)(p<0.001). Significant positive correlation were found between QTc and age, glucose, blood pressure in male subjects. There were a positive correlation between QTc and age, glucose, blood pressure, blood chlesterol, LDL-cholesterol, triglyceride, fasting insulin, HOMA index and negative correlation between QTc and HDL-cholesterol in female subjects. With multiple regression analysis, age (beta=0.480, p<0.001) and diastolic blood pressure (beta=0.280, p<0.001) were predictors of QTc in men, age (beta=0.321, p=0.008), diastolic blood pressure (beta=0.324, p=0.006) and HOMA index (beta=3.508, p=0.033) were predictors of QTc in women.
CONCLUSION
This study shows that QTc was more prolonged in female than in male among Korean healthy persons. In normoglycemic female subjects, there was correlation between insulin resistance and the prolongation of QTc.