Abstract: Background　Low diastolic blood pressure（DBP） is common in the elderly.However，the antihypertensive targets for the elderly in various hypertension guidelines usually only focus on systolic blood pressure，with less attention paid to DBP，and the maintenance level of DBP is still unclear.Objective　To explore the influencing factors of and 10-year survival outcome associated with 24-hour ambulatory DBP in the elderly.Methods　We enrolled 787 retired veterans（65-95 years old） who received inpatient services from Chinese PLA General Hospital of Southern Command during 2003 to 2008，and stratified them into three groups by 24-hour ambulatory DBP：<70 mm Hg group（n=352），70-80 mm Hg group（n=346） and > 80 mm Hg group（n=89）.We used multiple linear regression analysis to identify the associated factors of 24-hour ambulatory DBP.We collected the survival status of all groups during a 10-year follow-up，and explored it with Kaplan-Meier survival analysis.Results　The mean 24-hour ambulatory DBP for all the participants was（71±8）mm Hg.Those aged 65-79 year showed higher mean 24-hour ambulatory DBP than those aged 80-95 years（P<0.05）.Multiple linear regression analysis showed that age，BMI，heart rate，24-hour ambulatory SBP and hemoglobin were the influencing factors of 24-hour ambulatory DBP（P<0.05）.<70 mm Hg group aged 65-79 years showed higher prevalence of coronary heart disease and myocardial infarction than other two groups of the same age group（P<0.017）.And >80 mm Hg group aged 65-79 years demonstrated higher prevalence of hypertension compared with other two groups of the same age group（P<0.017）.The prevalence of coronary heart disease decreased successively in those aged 80-95 years in <70 mm Hg group，70-80 mm Hg group，and >80 mm Hg group（P<0.017）.Analysis with Cox proportional hazards regression model revealed that compared with 24-hour ambulatory DBP <70 mm Hg，24-hour ambulatory DBP >80 mm Hg was associated with 3.527〔95%CI（1.119，11.113）〕 times high risk of death from cardiovascular diseases in age group of 65-79（P<0.05）.However，in those aged 80-95 years，24-hour ambulatory DBP was not associated with the death from cardiovascular diseases（P>0.05）.The median survival time of <70 mm Hg group，70-80 mm Hg group，and > 80 mm Hg group was 149.27，161.11 and 161.65 months，respectively，showing a significant intergroup difference（P<0.05）.Conclusion　The 24-hour ambulatory DBP in the elderly is affected by age，BMI，heart rate，24-hour ambulatory SBP and hemoglobin.It plays an important role in the onset of coronary heart disease，myocardial infarction and hypertension，and may affect the 10-year survival of the elderly.The appropriate DBP target level may be 70-80 mm Hg for those aged 65-79 years，and may be higher（>80 mm Hg） for those aged 80 or over.

Key words: Blood pressure determination, Diastolic pressure, Aged, Ambulatory blood pressure monitoring, Root cause analysis, Prognosis

摘要： 背景　老年人普遍存在低舒张压现象，但目前国内外高血压相关指南对于老年人的降压目标往往仅关注收缩压，对于舒张压的关注较少，舒张压维持水平不明确。目的　探讨老年人24 h动态舒张压的影响因素，以及24 h动态舒张压对老年人10年生存预后的影响。方法　选取2003—2008年在中国人民解放军南部战区总医院住院的军队离退休老年人787例（年龄65~95岁），根据其24 h动态舒张压水平分为<70、70~80、>80 mm Hg三组，例数分别为352、346、89例。采用多元线性回归分析老年人24 h动态舒张压的影响因素；比较三组随访10年期间的死亡情况，采用Kaplan-Meier生存函数比较三组随访期间的生存时间。结果　老年人的24 h动态舒张压为（71±8）mm Hg，65~79岁者高于80~95岁者（P<0.05）。多元线性回归分析结果显示，年龄、BMI、心率、24 h动态收缩压、血红蛋白是老年人24 h动态舒张压的影响因素（P<0.05）。在65~79岁老年人中，24 h动态舒张压<70 mm Hg者冠心病、心肌梗死患病率高于70~80、>80 mm Hg者，>80 mm Hg者高血压患病率高于<70、70~80 mm Hg者（P<0.017）；在80~95岁老年人中，<70 mm Hg者冠心病患病率高于70~80 mm Hg者，70~80 mm Hg者冠心病患病率高于>80 mm Hg者（P<0.017）。Cox风险比例回归模型显示：对于65~79岁老年人，24 h动态舒张压>80 mm Hg者因心血管疾病死亡风险是<70 mm Hg者的3.527倍〔95%CI（1.119，11.113），P<0.05〕；对于80~95岁老年人，24 h动态舒张压不是其因心血管疾病死亡的影响因素（P>0.05）。三组中位生存时间分别为149.27、161.11、161.65个月，三组生存曲线比较，差异有统计学意义（P<0.05）。结论　老年人的24 h动态舒张压受年龄、BMI、心率、24 h动态收缩压、血红蛋白的影响，在冠心病、心肌梗死、高血压的发病中起重要作用，会影响老年人的10年生存预后。65~79岁老年人的舒张压控制在70~80 mm Hg可能较为合适，≥80岁老年人的舒张压可能更适合维持在较高水平（>80 mm Hg）。

关键词: 血压测定, 舒张压, 老年人, 动态血压监测, 影响因素分析, 预后