Heart rate, age and the risk progression to kidney failure in patients with CKD

Background and methods: Since heart rate (HR) isa cardiovascular risk factor and a marker of sympatheticactivity, we tested the predictive value of HR forprogression to kidney failure in a well characterizedcohort of 759 patients with stage 2-5 CKD followed upfor 29 ± 11 months.Results: Overall, a total of 244 patients had renalevents. In an unadjusted analysis by age tertiles thepredictive value of HR for renal events was apparentonly in patients in the third age tertile (older than68 years) but not in those in the first two tertiles indicatingeffect modification by age of the HR – progressionto kidney failure relationship. In a multiple Coxregression model adjusting for potential confounders,a 5 beats/min increase in HR entailed a 16% risk excess(Hazard Ratio = 1.16, P = .004) for renal eventsin patients in the third age tertile but no excess riskfor the same events in patients in the first two tertiles.A statistically significant interaction (P<.001) was alsofound between age and the risk for renal events associatedwith proteinuria.Conclusions: Heart rate is an independent age-dependenteffect modifier for progression to kidney failure inCKD patients. This observation generates the hypothesisthat high sympathetic activity is a relevant riskfactor for adverse renal outcomes in elderly patientswith CKD.