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Original Investigation
February 2017

Resting Heart Rate and Long-term Outcomes Among the African American PopulationInsights From the Jackson Heart Study

Author Affiliations
  • 1Duke Clinical Research Institute, Durham, North Carolina
  • 2Department of Medicine, University of Mississippi School of Medicine, Jackson
  • 3Department of Medicine, Duke University School of Medicine, Durham, North Carolina
  • 4Center of Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson
JAMA Cardiol. 2017;2(2):172-180. doi:10.1001/jamacardio.2016.3234
Key Points

Question  What is the prognostic utility of resting heart rate in African American individuals?

Findings  In this cohort study of 5261 African American participants in the Jackson Heart Study, resting heart rate was associated with significantly increased mortality and heart failure hospitalization before and after adjustment for comorbid conditions. With adjustment, every 5–beats per minute increase in heart rate was associated with a significant 14% increase in the hazard of mortality and a significant 10% increase in the risk for heart failure hospitalization.

Meaning  Higher baseline heart rate is associated with increases in mortality and heart failure hospitalization among African American individuals in the Jackson Heart Study.

Abstract

Importance  Increased resting heart rate is associated with worse outcomes in studies of mostly white populations, but its significance is not well established in African Americans persons whose cardiac comorbidities and structural abnormalities differ.

Objective  To study the prognostic utility of heart rate in a community-based African American cohort in the Jackson Heart Study.

Design, Setting, and Participants  A total of 5261 participants in the Jackson Heart Study, a prospective, community-based study in Jackson, Mississippi, were evaluated. Baseline heart rate was assessed by quintiles and as a continuous variable. All participants with baseline heart rate documented by a 12-lead electrocardiogram without pacing or atrial fibrillation noted on their baseline Jackson Heart Study examination were included in the study. Follow-up began September 26, 2000, and was completed December 31, 2011. Data analysis was performed from July to October 2015.

Main Outcomes and Measures  Unadjusted and adjusted associations between heart rate and all-cause mortality and heart failure hospitalization using Cox proportional hazards regression models.

Results  Of the 5261 individuals included in the analysis, 1921 (36.5%) were men; median (25th-75th percentile) age was 55.7 (45.4-64.8) years. Median (25th-75th percentile) baseline heart rate was 63 beats per minute (bpm) (57-71 bpm). The highest heart rate quintile (73-118 bpm) had higher rates of diabetes (398 [37.4%]; P < .001) and hypertension (735 [69.1%]; P < .001), higher body mass index (median [IQR], 32.4 [28.1-38.3]; P < .001), less physical activity (0 hours per week, 561 [52.8%]; P < .001), and lower β-blocker use (73 [6.9%]; P < .001) compared with lower quintiles. Caffeine intake (from 80.7 to 85.5 mg/d; P = .57) and left ventricular ejection fraction (from 62% to 62.3%; P = .01) were similar between groups. As a continuous variable, elevated heart rate was associated with increased mortality and heart failure hospitalizations, with adjusted hazard ratios for every 5-bpm increase of 1.14 (95% CI, 1.10-1.19) and 1.10 (95% CI, 1.05-1.16), respectively. Similar patterns were observed in comparisons between the highest and lowest quintiles.

Conclusions and Relevance  Higher baseline heart rate was associated with increased mortality and heart failure hospitalizations among African American participants in the Jackson Heart Study. These findings are similar to those seen in white populations, but further study is needed to understand whether African American individuals benefit from interventions targeting heart rate reduction.

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