| Abstract: | Background and objectives: Mortality risk of resting heart rate (RHR) has been shown to be an independent risk factor for mortality but attracted limited attention, particularly compared to hypertension. We focused on high normal RHR (80-99 beats/min), and sought equivalent risks at levels of blood pressure in hypertension.Methods: The cohort, 515,303 subjects free of heart disease, recruited successively from a health surveillance program between 1994 and 2008. Resting HR was determined from ECG. Deaths, 16,849, were identified from national death file as of 2011. A CVD-free sub-cohort was created by excluding those with hypertension, diabetes, smoking or high cholesterol. Life table method for life expectancy and Cox models for Hazard Ratios were calculated using RHR at 60-69/min and BP at ≦120/80 mmHg, as a common reference.Results: One quarter of the cohort had high normal RHR, but only 1/3 of high normal RHR had hypertension, implying a limited contribution of risks from hypertension to RHR. High normal RHR (80-99/min) as a whole had similar all-cause mortality risks (1.73), and similar number of life years shortened (6.7 years) as hypertension (≧140/90 mm Hg), but larger than JACC hypertension (≧130/80). RHR at 90-99/min had similar mortality risks (2.17) and years shortened (9.5 years) as Grade 2 hypertension (≧160/100 mmHg). In these comparisons, HR for CVD mortality, however, were slightly smaller for high normal RHR than hypertension. Other than increased CVD mortality, high normal RHR had more increases in diabetes, cancer, cirrhosis, kidney and COPD, Mortality risk of hypertension amplified by 20% when combined with high normal RHR.Conclusion: High normal RHR had larger risk than hypertension with BP at≧130/80, but similar as BP at ≧140/90 mmHg. RHR is as important as hypertension, in terms of all-cause mortality or in number of life years shortened. The CVD mortality risks of RHR, however, were slightly less, implying a more important role of hypertension in CVD. |
