Relation of heart rate at rest and mortality in the Women's Health and Aging Study

Increased heart rate (HR) has been shown to be associated with increased risk of all-cause and heart disease mortality. However, HR as a health indicator in disabled older women has not been closely examined. The purpose of this study is to assess the association between HR and 3-year mortality in disabled older women. HR at rest was measured using the electrocardiogram. Three groups were categorized by baseline HR (beats per minute): (1) <60, (2) 60 to 89, and (3) >/=90. The survival rate over 3 years was examined. For the total population, age-adjusted 3-year mortality was nearly 40% for the HR >/=90 group, compared with <20% mortality in the HR 60 to 89 group. Women with a HR <60 beats/min had similar mortality to those with HRs 60 to 89 beats/min. Among women with no heart disease and normal electrocardiograms, mortality was slightly lower in all groups, but the association of elevated HR with increased mortality remained. In Cox proportional hazard models, after adjustment for age, number of diseases, medications, blood pressure, smoking status, body mass index, ankle-brachial index, activity status, physical performance score, and forced expiratory volume in the first second, there remained a twofold increase in the risk of death for the HR >/=90 group. Subclinical conditions not measured in this study, such as mild heart failure, may be associated with both increased HR and mortality; this may explain the relation. In patients with and without heart disease, further investigation of cardiovascular status may be warranted if their HR is >/=90 beats/min.