Relationships Between Cumulative Resting Heart Rate and the Incidence of Cardiovascular Events and All-Cause Mortality - Post Hoc Analysis of STEP Trial Data.

Background: The long-term effects of cumulative resting heart rate (cumRHR) on the incidence of cardiovascular events and all-cause mortality in older (age ≥60 years) hypertensive populations remain unclear. Therefore, the aim of this study was to investigate the association between cumRHR and cardiovascular events and all-cause mortality.

Methods and results: This post hoc analysis used data from the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial of 7,517 patients in whom resting heart rate (RHR) was measured at 0, 3, 6, 9, and 12 months. "cumRHR" refers to the weighted mean of the RHR for each time interval. Participants were divided into quartiles (Q1-Q4) based on cumRHR. After adjustment for potential confounders and using Q3 (72.19-75.88 [beats/min] × year) as the reference, patients in Q4 (75.94-109.44 [beats/min] × year) had higher risks of the primary outcome (a composite of stroke, acute coronary syndrome, acute decompensated heart failure, coronary revascularization, atrial fibrillation, and death from any cardiovascular cause) (hazard ratio [HR] 2.21; 95% confidence interval [CI] 1.42-3.43; P<0.001), major adverse cardiovascular events (HR 1.93; 95% CI 1.18-3.16; P=0.009), and stroke (HR 3.55; 95% CI 1.42-8.86; P=0.007) and those in Q1 (44.50-68.44 [beats/min] × year) had an increased risk of the primary outcome (HR 1.71; 95% CI 1.08-2.71; P=0.02). No such trends were observed for all-cause mortality. A U-shaped relationship was observed with the primary outcome, with higher risk for both very low or very high cumRHR levels compared with midrange values.

Conclusions: Both low and high cumRHR levels were associated with higher risk of cardiovascular events in older patients with hypertension.