| BackgroundOrthostatic hypotension(OH) is common in the elderly and likely related to future cardiovascular disease (CVD) or mortality. Poor attention was paid on OH because of its nonspecific symptoms and low diagnosis.The relationship between orthostatic hypotension and antihypertensive therapy is unclear. The study on orthostatic hypotension in larger population in our country remains to be established.Objective1.To assess the prevalence and risk factors of orthostatic hypotension (OH) in the elderly;2.To determine impact of medicine on orthostatic hypotension in elderly hypertensives;3. To investigate the association between orthostatic hypotension and cardiovascular risk.Subjects and Methods1.To assess the prevalence and risk factors of orthostatic hypotension (OH) in the elderly,data on a total of 1455 people (1174 aged more than 65 years and 281 aged less than 65 years)underwent health screening physical examination through self-made questionnaire in Guangzhou military region were collected. The orthostatic blood pressure and heart rate were measured in supine position after resting for more than 5 minutes and at 0 and 2 min after standing. Orthostatic hypotension was defined as 20 mm Hg or greater decrease in SBP or/and 10 mmHg or greater decrease in DBP after standing. Subjects were divided into OH positive group and OH negative group. General characteristics, comorbid disease and risk factors were analyzed between the two groups.2. To determine the impact of antihypertensive treatment on orthostatic hypotension and the optimal blood pressure range in the individuals with orthostatic hypotension and hypertension, 849 primary hypertensives (including 250 OH positive and 599 OH negative) from the population with complete blood pressure data in part 1 were selected in the study. The prevalence of OH was analyzed according to the blood pressure grading, blood pressure control levels and antihypertensive therapy status.3. To investigate the association between orthostatic hypotension and cardiovascular and cerebrovascular diseases, 293 OH positive and 819 OH negative individuals were enrolled in the research. All participants were followed-up until the 28 March 2011(mean 315.6 days) through telephone and inpatient medical records. The primary endpoint was occurrence of emerging cardiovascular or cerebrovascular events (including angina, fatal or nonfatal myocardial infarction, congestive heart failure, sudden cardiac death, ischemic and hemorrhagic stroke).4. Statistical analysis: A database was created by SPSS 18.0 after quality examination of data.Continuous variables were reported as mean±SD and analyzed by t test or analysis of variance;categorical variables were reported as sample rate and compared using the chi-square or Fisher′s exact test;Risk factors of orthostatic hypotension were studied by unconditioned Logistic regression analysis; Multivariate logistic regression analyses were used to determine the relationship between orthostatic hypotension and cardiovascular and cerebrovascular diseases. A p-value of less than 0.05 was considered significant.Results1. Current status of orthostatic hypotension (OH) in the elderlyA total of 1174 individuals aged more than 65y (mean age 81.8 years, 95.6% male) and 281 aged less than 65y(mean age 52.4 years, 94.3% male)were enrolled into the study. Among the total study participants (n=1455) at the baseline,there were 325 OH positive individuals,including 24 aged less than 65y and 301aged more than 65y,and the prevalence of OH in former group was significantly lower than latter group.People aged more than 65 years were divided into elderly (65-79y) and very elderly (≥80y) in a boundary point of 80 years, the prevalence of OH in the latter group was higher than that in the former group (27.2%vs21.0%), and significant differences were observed (P=0.038). In addition, asymptomatic OH (AOH) accounts for the vast majority of OH when compared with the symptomatic form (87.7%vs12.3%).Among the people aged more than 65 years,OH positive individuals were older than OH negative individuals. Furthermore, the orthostatic hypotension group had a significantly higher blood pressure,creatinine concentration and slower HR and postural blood pressure. Significant differences could be seen between the two groups. Moreover,OH was correlated with statistically significant higher prevalence of hypertension, previous CVD(including myocardial infarction and heart failure), ischemic stroke, diabetes mellitus and impaired glucose tolerance(IGT()The prevalence of the previous diseases were 83.1% vs 68.6%;12.0% vs 6.4%;13.0% vs 6.3%;22.3% vs 16.2%;47.2% vs 29.2%;10.6% vs 7.0%),except hemorrhagic stroke(2.7% vs 2.7%).After adjustment for age, creatinine concentration and sitting heart rate, logistic regression analysis showed that hypertensio(nOR:1.543, 95%CI:1.066-2.235,P=0.022),coronary heart disease(OR:2.051,95%CI:1.489-2.826,P<0.001), previous diabetes(OR:1.409,95%CI:1.062-1.870,P=0.017)and supine blood pressure were predisposing determinants for orthostatic hypotension.2. The relationship between orthostatic hypotension and antihypertensive treatment in elderly hypertensives.The subjects of this branch study were 894 primary hypertensives(mean age 81.9±4.1years,95.3% male)selected from part 1.Overall,250 (29.4%) of 894 patients experienced OH. No significant difference could be observed in the prevalence of OH between elderly and very elderly group(30.1%vs27.3%,P=0.442).Companied with blood pressure stage heightening gradually, the prevalence of OH was seemed to be also higher. However, only stage 3 hypertensives had a significant higher prevalence of OH than stage1 and 2,(34.1%vs24.5,26.6%,;P<0.05),while no significant difference could be observed between stage1 and 2(P=0.621).By analyzing the current blood pressure control,following results were obtained:individuals with a systolic blood pressure ranging from 130-139 mmHg and/or a diastolic blood pressure ranging from 70-79mmHg had a significant lower prevalence of OH(21.4%vs 23.8%;P<0.05).The prevalence of OH was fairly similar between those who received antihypertensive therapy and those who did not (30.5% vs 23.4%;P=0.11). The odds of OH did not increase with the types and the overall number of drugs being taken.3. The relationship between orthostatic hypotension and risk of future cardiovascular disease (CVD)1112 patients (293 OH positive and 819 OH negative) with a mean age of 81.1 years were followed-up until the 28 March 2011(mean 315.6 days).398 individuals underwent an experience of readmission(35.8%).Significant differences could be found in the rate of readmission between OH positive and OH negative(45.1% vs 32.5%);The rates of awareness and first diagnosis of OH were 2.0% and 2.3% respectively.Altogether,81 individuals (7.3%) suffered from cardiovascular event and 31 (2.8%) were diagnosed with incident stroke. Significant differences could be found in the prevalence of total cardiovascular event and heart failure (4.3% vs 8.3%,0.4% vs 2.2%) rather than cerebrovascular event between the elderly and very elderly;The rates of total cardiovascular event,angina and myocardial infarction in OH positive group were significantly higher than in OH negative group(13.3% vs 5.1%;7.5% vs 3.7%;4.8% vs 0.5%);In the elderly group, the incidence of overall cardiovascular event, angina and myocardial infarction is significantly higher in the OH positive group when compared with that in the OH negative group; while, in the very elderly group, the incidence of overall cardiovascular event and myocardial infarction is significantly higher in the OH positive group when compared with that in the OH negative group. However, there is no significant difference of cerebrovascular events between the elderly and the very elderly group.At the baseline,only evidence of OH and subsequent angina(P=0.009,HR:2.135,95% CI:1.211-3.765)and MI (P<0.001,HR:10.224, 95% CI:3.338-31.319) could be found;Although the associations were attenuated after adjusting for age,supine blood pressure,hear rate,history of hypertension,MI,HF,stroke and pathoglycemia,statistical differences still existed [angina (P=0.011,HR:2.122,95% CI:1.184-3.802) and MI (P<0.001,HR:8.995,95% CI:2.909-27.819)]Conclusions1. Orthostatic hypotension is common in elderly and retired patients which increased with age. Asymptomatic OH (AOH) accounts for the vast majority of OH. Comorbid hypertension,diabetes mellitus, and cardiovascular disease may increase the risk of orthostatic hypotension.2. Orthostatic hypotension can easily observed in elderly hypertensives,especially those with cardiovascular diseases;Companied with blood pressure stage heightening gradually, the prevalence of OH was also higher;A systolic blood pressure ranging from 130-139 mmHg and/or a diastolic blood pressure ranging from 70-79mmHg might be the appropriate blood pressure goal for the patients with hypertension and orthostatic hypotension.3. The rate of awareness and diagnosis of orthostatic hypotension were pretty low;Orthostatic hypotension could increase the rate of readmission and was a robust predictor of angina and myocardial infarction in the elderly. |
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