Abstract
BACKGROUND: Insulin resistance is associated with increased sympathetic and reduced parasympathetic activity. Resting heart rate reflects autonomic activity. Therefore, we examined the associations of resting heart rate with insulin resistance, cardiovascular events and mortality in the moderate chronic kidney disease (CKD) population. METHODS: Four hundred and sixty participants with MDRD GFR <60 ml/min/1.73 m(2) in the limited access Atherosclerosis Risk in Communities (ARIC) study database were divided into four resting heart rate groups: <60, 60-74, 75-89 and >or=90/min. The prevalence of metabolic syndrome at baseline across the groups was examined. Time to cardiovascular composite (myocardial infarction or fatal coronary artery disease event or stroke or coronary revascularization procedure) and time to all-cause death were examined in multivariate Cox models. RESULTS: The prevalence of metabolic syndrome in the <60, 60-74, 75-89 and >or=90/min groups were 41, 44, 69 and 82% (P < 0.001), respectively. In a multivariate Cox model adjusted for demographics, comorbidity, haemoglobin and physical activity, compared to the 60-74/min group, the hazard ratios of cardiovascular composite in <60, 75-89 and >or=90/min groups were 1.27 (95% CI 0.75-2.16), 1.79 (95% CI 1.07-2.99) and 1.37 (95% CI 0.54-3.44), respectively. In a similar model, the hazard ratios of death were 1.47 (95% CI 0.85-2.53), 3.11 (95% CI 1.93-5.02) and 3.97 (95% CI 1.99-7.94), respectively. CONCLUSIONS: Resting heart rate is associated with metabolic syndrome in moderate CKD. Higher resting heart is associated with increased mortality and possibly cardiovascular events in this population. Interventional studies to examine whether a target resting heart rate of 60-74/min improves cardiovascular outcomes and survival in moderate CKD are warranted.