Change In Resting Heart Rate And Subsequent Risk Of Hypertension

BackgroundChanges in baseline resting heart rate(RHR)appear to predict new-onset hypertension(NOH).However,RHR is a dynamic anthropometric parameter;thus,the association between changes in RHR and NOH requires further investigation.MethodsThis observational retrospective cohort study was performed at Nanfang Hospital in Guangzhou City,China between October 2011 and August 2016.We studied 10,403 participants who were initially normotensive and who had at least one routine health examination at baseline and one year later during 2011-2016.We evaluated the changes in RHR between the baseline and the examination after one year.We defined hypertension as systolic blood pressure(SBP)≥140 mmHg and/or diastolic blood pressure(DBP)≥90 mmHg.First,we used smooth curve fitting adjusted for gender,baseline age,and SBP to assess the potential association betweenΔRHR and the risk of hypertension.Subsequently,subjects were divided into three groups according to a one-year change in RHR:In group 1,RHR decreased(ΔRHR<0 beats per minute(bpm));in group 2,RHR was unchanged(0≤ΔRHR<10 bpm);in group 3,RHR increased(ΔRHR≥10 bpm).Cox proportional hazard models were performed to calculate the hazard ratios(HRs)and 95%confidence intervals(CIs)of NOH(the group with stable RHR was used as the reference).Multivariable models were built to observe the influence of potential covariates and further verify the association between ΔRHR and NOH.We analyzed interactions between ΔRHR and other risk factors collected at baseline,and we categorized the HRs for the association of RHR change[as a continuous exposure(per 10-bpm increase)]and the risk of NOH by age(<45,≥45)and gender.Finally,we analyzed the combined effect of baseline RHR(<70,70-80,≥80bpm)and ΔRHR on NOH.ResultsDuring a mean follow-up period of 2.42 years,1,173(11.28%)participants developed hypertension.Smooth curve fitting after adjustment for gender,baseline age,and SBP indicated that,generally,the risk of NOH ascended with the increase inΔRHR.The cumulative incidences of NOH for the group with decreased RHR,stable RHR and increased RHR were 10.5%,11.4%and 13.1%respectively(P=0.018).After adjusting for age,gender,SBP,DBP,RHR and other confounders obtained at baseline,and compared with participants with unchanged RHR participants with decreased RHR had a 17%decreased risk of NOH(adjusted hazard ratio:0.83,95%CI:0.730.95),whereas subjects with RHR that increased≥10 bpm had a 23%increased risk of NOH(adjusted hazard ratio:1.23,95%CI:1.04-1.46).No significant interaction was found between ΔRHR and other risk factors collected at baseline.Results stratified by age were consistent while stratified analysis was performed by gender,no appreciable association was found in women.Compared with subjects with lower RHR at baseline and decreased RHR during the one year of follow-up,individuals with higher baseline RHR and increased RHR during one year of follow-up had a significantly higher risk of hypertension.ConclusionsIncrease in RHR for initially normotensive subjects is an independent risk factor for subsequent hypertension.