Midlife resting heart rate, but not its visit-to-visit variability, is associated with late-life frailty status in men with coronary heart disease

Background: Autonomic imbalance is linked with multiple health conditions, yet its associations with frailty were rarely studied. We assessed the relationship of resting heart rate (RHR) and visit-to-visit heart rate variability (HRV) with future frailty among elderly men with coronary heart disease (CHD). Methods: Three-hundred-six community-dwelling men with CHD who participated in the Bezafibrate Infarction Prevention (BIP) trial (1990-1998; mean age 56.6 +/- 6.5 years) underwent assessment of physical frailty in 2011-2013 (mean age 77.0 +/- 6.4 years). Mean RHR and visit-to-visit HRV were calculated from electrocardiogram as indicators of autonomic imbalance. Nominal logistic and linear regression models were used to assess the relationships of RHR and HRV with frailty status and its components (i.e. gait speed, grip strength, weight loss, exhaustion and activity), respectively. Adjustments were made for various demographic, clinical and metabolic covariates. Results: Of the 306 men, 81 (26%) were frail and 117 (38%) were prefrail. After controlling for potential confounders, RHR, but not visit-to-visit HRV, was associated with higher odds of being prefrail [OR = 1.44 (95%CI 1.15, 1.79)] and frail [OR = 1.35 (95%CI 1.03, 1.77)]. Each 5-bpm increase in RHR was associated with weaker grip (beta= -1.12 +/- 0.32 kg; p-value < .001) and slower gait speed (beta = 0.19 +/- 0.08s/m; p-value = .022). Conclusions: Midlife RHR may be associated with late-life frailty in men with CHD.