Association of clinic and ambulatory heart rate parameters with mortality in hypertension

Abstract

Resting heart rate (HR) taken in the office has been shown to be associated with cardiovascular outcomes in the general population, hypertension and heart failure. It is unknown whether 24-h oscillographic pulse rate measurement as an approximation of HR derived from ambulatory blood pressure monitoring (ABPM) associates with cardiovascular outcomes in hypertensive patients.Methods: We evaluated ABPM recordings from 56 901 patients with complete 3373 421 HR measures entering the final analysis from the Spanish Blood Pressure Monitoring Registry for a median follow-up time of 5.1 years. We explored the association of office HR, mean 24-h HR, mean day HR, mean night HR as well as day–night HR differences, morning mean HR, morning HR surge and night peak HR to all-cause death, cardiovascular death and noncardiovascular death. Data were analyzed by Cox regression analysis, analysis of variance and chi-square test.

Results: The Spanish ABPM Registry recorded data in 223 primary care centers in Spain from 2004 until 31 December 2014 at the end of recruitment. Office HR was 3.5 bpm higher than mean 24-h HR, office mean HR versus mean night was 10.4 bpm higher and mean day versus mean night HR 9.3 bpm higher, while there were no relevant difference between office and mean day HR. Office mean, 24-h day and night HR more than 90 bpm were associated with an increased risk for all-cause and noncardiovascular death, whereas for cardiovascular death only mean night HR was predictive. The strongest association to all-cause death was observed with mean night HR [hazard ratio 3.80 (2.87–5.03)], mean 24-h HR [2.85 (2.30–3.54)] and mean day HR [2.22 (1.83–2.70)]. Day-night dipping of more than 8 bpm was associated with a 20% lesser risk on all-cause, cardiovascular and noncardiovascular death. Results were robust after adjusting for relevant risk indicators.

Conclusion: HR parameters derived from ABPM provide important information, in particular association with death by mean night HR, mean 24-h HR and reduced day–night HR dipping less than 8 bpm superior to office HR.