Risk Factors Of Isolated Systolic Hypertension And Antihypertensive Efficiency Of Bisoprolol And Diltiazem

Background:Isolated systolic hypertension(ISH) was the main risk factor of cardiovascular diseases of the elderly. Although many clinical trials documented the benfits of antihypertensive therapy to the elderly,treatment and control rate of ISH was low. Ob j ect i ves:1. To investigate whether risk factors of ISH were different from that of other hypertension subtypes and normortensives.2. To explore the association between obesity and high sensitive C-reactive protein(hsCRP),an inflammatory factor, in elderly people diagnosed with ISH between different gender.By identifying associations between reproductive-related factors and ISH,the study aimed to discusses causes of the high prevalence of ISH with elderly women.3. By investigating the antihypertensive effect of bisoprolol and slow-release diltiazem,the study aimed to evaluate the negative frequency effect on blood pressure in elderly patients with ISH. Methods:1. A total of127subjects with ISH were enrolled randomly.Datas about age, sex,body mass index(BMI),waist circumference(WC), cigarette smoking, alcohol consumption, physical activity, resting heart rate, complications, family history, lipid, fasting blood-glucose, hsCRP were recorded. Subjects with ISH were compared with other hypertensive subtypes and normotensives on all the items above.The relationship between hsCRP and cardiovascular risk stratification, lipid and blood-glucose was performed with multiple linear regression analysis. The prevalence of cardiovascular complications in different level of DBP was also analyzed.2.72female subjects with ISH were selected randomly.72cases age matched men(n=72) and normotensives women (n=72) were choosed as control groups. Datas were collected for BMI, WC,WHR etc. Fasting peripheral venous blood samples were obtained to determine hsCRP. Factors above were compared between different gender. The reproductive-related factors were compared between ISH and normotentives controls. Associations between reproductive-related factors and with the prevalence of ISH were analyzed using logistic regression. Taking whether or not be ISH as the dependent variable, the reproductive factors as the independent variables, Logistic regression analysis was performed.3.240subjects with ISH were randomized to receive bisoprolol(n=75), slow-release diltiazem (n=81) or nifedipine controlled release(CR) tablet (n=84) respectively for8weeks. The antihypertensive effect and blood pressure control rates in diltiazem and bisoprolol was compared with nifedipine CR tablet. Linear correlation analysis was performed to evaluate the association between the reduction of blood pressure and heart rate. Results:1. In ISH group cases aged60years or older, and the proportion of women was higher than SDH,IDH group and the normomentives. The rate of current smokers in ISH was less than IDH group (P<0.01), while passive smoking rate was higher than SDH,IDH and normomentives group (P<0.05). When BMI was equal or greater than28kg/m2there was no significant difference between ISH and SDH, but that of in ISH was lower than IDH group (P<0.05). Fasting blood glucose and triglyceride in ISH group was lower than that of IDH group (P<0.01).The hsCRP level in ISH group was significantly higher than the SDH, IDH and normotensives (P<0.01).Multiple linear regression showed that risk stratification,WC, low density lipoprotein, fasting blood glucose was the influencing factors when the hsCRP in ISH group regarded as the dependent variable and risk factors as independent variable.The hsCRP was significantly higher in cardiovascular stratification risk extremely high group than that in other groups.(P<0.01). In subgroup of DBP less than70mmHg the prevalence of stroke was higher than that DBP between71-79and80-89mmHg subgroups respectively.2Taking BMI as standard,there was no significant difference about obesity between different gender. The proportion of the female whose WC was higher than80cm was66.7%and that of WHR higher than0.85was62.5%.While that of the male,namely WC was higher than85cm or WHR higher than0.90was48.6%and44.4%, respecctively. The proportion of abdominal obesity of the female was higher than the male significantly.The median of hsCRP of the female(2.9mg/L)was higher significantly than that of the male (2.6mg/L).Only the WC of female was positively related with the level of hsCRP. The regression equation was Y=-4.02+0.27X. But for men, WC, BMI, WHR etc was not related with hsCRP. The logistic regression was performed between the ISH and risk factors.The results was that age at first delivery and menopause was protective factors,hypertension in pregnancy was risk factor.3.SBP and DBP were both decreased significantly when taking bisoprolol and slow-release diltiazem as fundamental antihypertensive therapy for8weeks respectively.(P<0.01). The reduction of blood pressure caused by bisoprolol and diltiazem did not show any statistical significance when comparing to that of nifedipine CR tablets. Blood pressure control rates of slow-release diltiazem and bisoprolol alone was9.2%and9.9%respectively, both of which were lower than that of nifedipine CR tablets. With the combination of fosinpril and nifedipine CR,there was no significant difference on blood pressure among all the3groups.The reduction of heart rate accompanied with bisoprolol and slow-release diltiazem was significant. There was not linear correlation between blood pressure and heart rate reduction. Linear regression analysis between blood pressure and heart rate in patients with ISH showed that there was a negative relationship between SBP and heart rate (r=0.60, P <0.01) and a positive relationship between DBP and heart rate (r=0.55, P<0.01). Conclusions:1. Adults at the age of60and more, female, passive smoking, abdominal obesity, low degree of culture and physical activity, hsCRP level and DBP less than70mmHg were the risk factors of ISH.The characteristic of middle-aged ISH primarily was BMI equaled or greater than28Kg/m2. Elderly ISH mainly characterized by the increase of WHR.HsCRP level, DBP less than70mmHg might participate in the risk stratification of ISH.Inflammation may participate the occurrence of ISH by the formation of risk factors.2Inflammatory reaction may participate in the pathogenesis of ISH of the female by abdominal obesity.3. Bisoprolol and slow-release diltiazem was not as effective as nifedipine CR as first-line monotherapeutic agents for the treatment of ISH in two weeks. The correlation between heart rate and blood pressure patients in ISH was different from the other types of primary hypertension. Strategy based on negative frequency and negative inotropic effect only is not appropriate to elderly patients with ISH in antihypertension therapy.