Analysis Of Correlation Between The Blood Pressure Variability And Renal Function In Male Elderly

Background and Objective:As one of the most important factors of cardiovascular diseases,hypertension had an elevating tendency in morbidity and mortality. In 2009, American Society of Hypertension Hypertension Collaborative Group(ASH) pointed out that the nature of hypertension was a complicated progressive vascular syndrome,on which many etiological factors interacting. Maybe some pathophysiological changes in target organs such as heart,kidney and brain,and some clinical or subclinical appearances would occur before the blood pressure elevated.Early detecting and interfering in vasculopathy and evaluating risk factors had an important meaning for "super prevention and treatment" in cardiovascular diseases.Many recently researches found that the parameters of blood pressure variability(BPV) not only had more valuable prediction than that tranditional markers such as systolic pressure,diastolic pressure and pulse pressure,but also had positive association with hypertensive target- organ damage(TOD).Moreover, some parameters of BPV can be as independent prognostic factors.The quantity of related articles refer to elderly or super-elderly was scarce,and the same case refer to interaction between the BPV and renal function(RF) in Chinese.Therefore,the aim of the present study was to investigate:1.the differences of indexes of ambulatory blood pressure monitoring(ABPM) in elderly and super-elderly. 2. the correlation between BPV and RF in Chinese male elderly and super-elderly.Methods:From January 2008 to December 2010, selected 485 old male patients(334 super-elderly) aged 60～103 years (79.83±10.16years, mean±SD) from geratic cardiology department of PLA General Hospital.Collected each patient's information by the way of clinical records retrieval,then entered the information into Excel database:①General information:age,height,weight,body mass index(BMI),history of disease,family history,status of therapy,total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),serum creatinine(Cr),blood uric acid(UA),blood glucose(Glu);②12 indexes of ABPM:24h systolic BP variability,24h diastolic BP variability,24h systolic BP load,24h diastolic BP load,systolic BP nocturnal fall,diastolic BP nocturnal fall,etc. Calculated eGFR by the formula of China modified MDRD.Cases of this study were divided into 3 groups by different eGFR(ml/min/1.73m2):eGFR>90,eGFR60-90,eGFR<60.(by K/DOQI).Compared general information and indexes of ABPM in different groups. By the age, all cases were divided into elderly group and super-elderly group,then compared the general information by t study, Pearson correlation and multiple regression analysis to evaluate the correlation between BPV and eGFR.All analyses were conducted using SPSS (version 13, SPSS Inc., Chicago, Illinois).Results:Age,UA, diabetes and coronary heart disease(CHD) had significant difference (P<0.001) in different eGFR levels. With decreasing of eGFR value, Age, UA, the prevalence of diabetes and CHD elevated obviously, whereas the prevalence of hypertension and antihypertensive had no significant deviation. Indexes of ABPM such as 24h systolic BP variability,daytime systolic BP,diastolic BP nocturnal fall had some extent changes.24h systolic BP variability and daytime systolic BP elevated with of eGFR value (P=0.023/P=0.044). On the contrary, diastolic BP nocturnal fall descented with decreasing of eGFR (P=0.027).Unexpected, traditional 24h systolic BP and 24h diastolic BP make no obvious change with decreasing of eGFR (P=0.112/P=0.643). The results of pearson correlation showed that there is significant correlation between 24h DBP load, daytime systolic BP and eGFR(r=0.18, P=0.027/r=-0.23, P=0.005) in elderly group, meanwhile, there is significant correlation between 24h systolic BP variability, diastolic BP nocturnal fall and eGFR(r=-0.32, P=0.003/r=0.24, P=0.019) in super-elderly group. The results of multiple regression analysis showed that hypertension and antihypertensive,UA,daytime systolic BP were associated with eGFR in older men and age,hypertension and antihypertensive,BMI,UA,24h systolic BP variability, diastolic BP nocturnal fall were associated with eGFR in very older men.Conclusions:This study verified further,according to statistics of indexs of ABPM and eGFR(by the formula of China modified MDRD),that parameters of BP variability, especially 24h systolic BP variability correlated with RF in Chinese male elderly. Apparente negative correlation between 24h systolic BP variability and eGFR existed in male super-elderly patients.Furthermore,this correlation was independent of other traditional risk factors.Different indexs of ABPM showed incompatible appearances in different aged patients.Cardivascular academic circles had been focusing on the variation of BP because of successive reports on prognostic value and correlation with hypertensive TOD of which,even some scholars suggested that the BP variability should be a new target point of therapy. Further study and discussion were needed.