Abstract 4988: Resting Heart Rate Predicts Coronary Events, but not Stroke, in Women
Resting heart rate reflects both sympathetic and parasympathic input to the sinus node, and has been proposed as a global indicator of autonomic tone. Heart rate independently predicts coronary risk in men, but this association has been weaker or absent altogether in women. We evaluated heart rate as a predictor of cardiovascular events in the Women’s Health Initiative. During 7.8 year follow up of 129,135 postmenopausal women, 2281 CHD events (myocardial infarction/coronary death) and 1877 strokes were identified by centrally-trained physician adjudicators. The relationship between cardiovascular events and heart rate (measured by radial pulse palpation for 30 seconds after women rested quietly for 5 minutes) was evaluated in Cox regression models adjusted for age, ethnicity, hypertension, diabetes, smoking, high cholesterol, depressive symptoms, self-reported nervousness, body mass index, physical activity, use of alcohol, statins or postmenopausal hormone therapy, dietary caffeine and saturated fat. Resting heart rate independently predicted CHD (hazard ratio 1.26, 95% confidence interval 1.11–1.42 for highest [>76 beats per minute] vs lowest quintile [≤62 beats per minute]; p=0.001), but not stroke (p value 0.64). The association of heart rate with CHD was weaker than for diabetes (HR 2.68, 95% CI 2.36–3.03; p<.001) or smoking (HR 2.32, 95% CI 2.03–2.65; p<.001), but stronger than saturated fat consumption (HR 1.13 per 5% increase, 95% CI 1.05–1.20; p<.001) or physical activity (HR 0.97 per 5 MET-h/wk increase, 95% CI 0.95– 0.99; p<.001). Change in heart rate from baseline to year 3 was not independently associated with either CHD or stroke. The relationship between heart rate and coronary events did not differ between white and minority women (p for interaction=0.45) or those with or without diabetes (p for interaction=0.31), but was stronger among women aged 50 – 64 years at baseline compared with those aged 65–79 years (p for interaction=0.009). Resting heart rate, a low tech, inexpensive measure of autonomic tone, independently predicts CHD, but not stroke, in women.