aImperial College London UK bDepartment of Cardiovascular Diseases, The Studies Coordinating Centre, Division of Hypertension and Cardiovascular Rehabilitation, University of Leuven, Leuven, Belgium cCentre for Epidemiological Studies and Clinical Trials, The Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China dHôpital Broca, Centre de Gerontologie, 54-56 rue Pascal, 75013 Paris France eLondon School of Hygiene and Tropical Medicine, London, UK.
J Hypertens. 2013 Sep;31(9):1868-75. doi: 10.1097/HJH.0b013e3283622cc6.
High blood pressure (BP) has been associated with increased risk of dementia. Concerns have been raised about lowering BP too far in the very elderly and thereby increasing risk. There is some evidence to suggest a potential 'J'-shaped relationship between DBP and risk of cognitive impairment. This was investigated using data from the HYpertension in the Very Elderly Trial (HYVET).
HYVET was a double-blind, placebo-controlled trial of antihypertensives in patients aged at least 80 years with an untreated SBP of 160-199 mmHg. Active medication was indapamide sustained release 1.5 mg+/- perindopril 2-4 mg to reach goal pressure of less than 150/80 mmHg. Incident dementia was a secondary endpoint and was not significantly different between the two treatment groups. The relationship between pressure and incident dementia was assessed using Cox proportional hazards regression with BP entered as either a discrete (quartile analysis) or continuous predictor variable. Achieved BP was calculated as the mean of all pressures from the 9 month visit onwards.
During a mean follow-up of 2.2 years 263 incident cases of dementia were diagnosed. After adjustment for various covariates, baseline DBP was inversely related to incident dementia (P=0.0064). Achieved DBP did not predict later dementia in the placebo group (P=0.43), but showed a U-shaped relationship in the active treatment group (P=0.0195). The relationship between incident dementia and DBP did however not differ significantly between the placebo and active treatment groups (P=0.38). SBP was not associated with incident dementia, at baseline (P=0.62) or during follow-up (placebo group P=0.13, active group P=0.36). Wider achieved pulse pressure (PP) was associated with increased risk of dementia in both treatment groups (placebo P=0.032, active P=0.0046). The same tendency was observed for baseline PP (P=0.095).
Wider PP may possibly indicate an increased risk for dementia. Active treatment may act to change the shape of the relationship between DBP and dementia. Future studies need to focus on exploring the ideal goal pressure for this age group.
高血压（BP）与痴呆风险增加有关。有人担心在非常高龄的人群中降压过低会增加风险。有一些证据表明舒张压（DBP）与认知障碍风险之间存在潜在的“J”形关系。这是使用 HYpertension in the Very Elderly Trial（HYVET）的数据进行的研究。
HYVET 是一项针对 80 岁以上、未治疗的收缩压（SBP）为 160-199mmHg 的患者的抗高血压药物双盲、安慰剂对照试验。活性药物是吲达帕胺缓释 1.5mg +/-培哚普利 2-4mg，以达到低于 150/80mmHg 的目标血压。新发痴呆是次要终点，两组之间无显著差异。使用 Cox 比例风险回归评估压力与新发痴呆之间的关系，血压以离散（四分位分析）或连续预测变量的形式输入。所达到的 BP 计算为从 9 个月就诊开始的所有压力的平均值。
在平均 2.2 年的随访期间，诊断出 263 例新发痴呆病例。调整各种协变量后，基线 DBP 与新发痴呆呈负相关（P=0.0064）。安慰剂组中达到的 DBP 不能预测随后的痴呆（P=0.43），但在活性治疗组中呈 U 形关系（P=0.0195）。然而，新发痴呆与 DBP 之间的关系在安慰剂和活性治疗组之间并无显著差异（P=0.38）。SBP 与基线时（P=0.62）或随访期间（安慰剂组 P=0.13，活性组 P=0.36）的新发痴呆无关。在两组中，达到的较宽脉冲压（PP）与痴呆风险增加相关（安慰剂 P=0.032，活性 P=0.0046）。基线 PP 也存在同样的趋势（P=0.095）。
较宽的 PP 可能表明痴呆风险增加。积极治疗可能会改变 DBP 与痴呆之间关系的形状。未来的研究需要集中探讨该年龄组的理想目标压力。
