Association between C-reactive protein and QTc interval in middle-aged men and women

Background: Both of prolonged QT interval and elevated C-reactive protein (CRP) levels are known to be risk factors of cardiovascular disease. To our knowledge, few studies have reported the direct relationship between CRP levels and the QT interval in middle-aged population. The objective of the present study was to examine the association of CRP level with QT interval. Methods and results: A total of 2471 men and 2287 women from the Korea n Health and Genome study underwent physical examination and completed a questionnaire. A 12-lead electrocardiogram (ECG) recording was obtained from each subject. Subjects who were taking statins, non-steroidal anti-inflammatory drugs (NSAID) and postmenopausal hormone replacement therapy, which are known to have an effect on CRP levels, were excluded. Geometric means of CRP levels were compared among three groups, which were classified by heart rate-corrected QT (QTc) interval: prolonged (>= 440 msec in men and >= 450 msec in women), borderline (420-439 msec in men and 430-449 msec in women) and normal (< 420 msec in men and < 430 msec in women) groups. The means of CRP level in women, though over normal range, increased significantly as QTc interval was longer, independent of confounding factors, while those of men were on the borderline of significance. However, compared to normal range of QTc interval, prolonged QTc interval was associated with elevated CRP level, defined as more than 95 percentile of CRP, in men and women, respectively. Conclusions: Prolonged QTc interval in middle-aged men and women is associated with the elevated CRP, independent of confounding factors.