Importance The benefit of blood pressure lowering for the prevention of dementia or cognitive impairment is unclear. Objective To determine the association of blood pressure lowering with dementia or cognitive impairment. Data Sources and Study Selection Search of PubMed, EMBASE, and CENTRAL for randomized clinical trials published from database inception through December 31, 2019, that evaluated the association of blood pressure lowering on cognitive outcomes. The control groups consisted of either placebo, alternative antihypertensive agents, or higher blood pressure targets. Data Extraction and Synthesis Data were screened and extracted independently by 2 authors. Random-effects meta-analysis models were used to report pooled treatment effects and CIs. Main Outcomes and Measures The primary outcome was dementia or cognitive impairment. The secondary outcomes were cognitive decline and changes in cognitive test scores. Results Fourteen randomized clinical trials were eligible for inclusion (96 158 participants), of which 12 reported the incidence of dementia (or composite of dementia and cognitive impairment [3 trials]) on follow-up and were included in the primary meta-analysis, 8 reported cognitive decline, and 8 reported changes in cognitive test scores. The mean (SD) age of trial participants was 69 (5.4) years and 40 617 (42.2%) were women. The mean systolic baseline blood pressure was 154 (14.9) mm Hg and the mean diastolic blood pressure was 83.3 (9.9) mm Hg. The mean duration of follow-up was 49.2 months. Blood pressure lowering with antihypertensive agents compared with control was significantly associated with a reduced risk of dementia or cognitive impairment (12 trials; 92 135 participants) (7.0% vs 7.5% of patients over a mean trial follow-up of 4.1 years; odds ratio [OR], 0.93 [95% CI, 0.88-0.98]; absolute risk reduction, 0.39% [95% CI, 0.09%-0.68%]; I2 = 0.0%) and cognitive decline (8 trials) (20.2% vs 21.1% of participants over a mean trial follow-up of 4.1 years; OR, 0.93 [95% CI, 0.88-0.99]; absolute risk reduction, 0.71% [95% CI, 0.19%-1.2%]; I2 = 36.1%). Blood pressure lowering was not significantly associated with a change in cognitive test scores. Conclusions and Relevance In this meta-analysis of randomized clinical trials, blood pressure lowering with antihypertensive agents compared with control was significantly associated with a lower risk of incident dementia or cognitive impairment.

中文翻译：

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血压降低与事件性痴呆或认知障碍的关联

重要性 降低血压对预防痴呆或认知障碍的益处尚不清楚。目的确定血压降低与痴呆或认知障碍的关系。从数据库开始到 2019 年 12 月 31 日发布的随机临床试验的 PubMed、EMBASE 和 CENTRAL 的数据源和研究选择搜索，评估了血压降低与认知结果的关联。对照组由安慰剂、替代抗高血压药或更高的血压目标组成。数据提取和综合数据由2位作者独立筛选和提取。随机效应荟萃分析模型用于报告汇总的治疗效果和 CI。主要结果和措施 主要结果是痴呆或认知障碍。次要结果是认知能力下降和认知测试分数的变化。结果 14 项随机临床试验符合纳入条件（96 158 名受试者），其中 12 项在随访中报告了痴呆（或痴呆和认知障碍的复合[3项试验]）的发生率，并被纳入初步荟萃分析， 8 人报告了认知能力下降，8 人报告了认知测试分数的变化。试验参与者的平均 (SD) 年龄为 69 (5.4) 岁，其中 40 617 (42.2%) 为女性。平均收缩压基线血压为 154 (14.9) mm Hg，平均舒张压为 83.3 (9.9) mm Hg。平均随访时间为 49.2 个月。与对照组相比，使用抗高血压药物降低血压与痴呆或认知障碍风险降低显着相关（12 项试验；92 135 名参与者）（在 4.1 年的平均试验随访中，7.0% 对 7.5% 的患者；优势比[OR]，0.93 [95% CI，0.88-0.98]；绝对风险降低，0.39% [95% CI，0.09%-0.68%]；I2 = 0.0%）和认知能力下降（8 项试验）（20.2% vs 21.1平均试验随访 4.1 年的参与者百分比；OR，0.93 [95% CI，0.88-0.99]；绝对风险降低，0.71% [95% CI，0.19%-1.2%]；I2 = 36.1%） . 血压降低与认知测试分数的变化没有显着相关性。结论和相关性 在这项随机临床试验的荟萃分析中，