title: Renin-angiotensin system blockade use and risks of cognitive decline and dementia: A meta-analysis.
abstract: OBJECTIVE
  To evaluate the effects of renin-angiotensin system blockade (RASB) and its classes on the incidences of cognitive decline and dementia.
  
  
  METHODS
  PubMed, the EMBASE database and Cochrane Library were searched through October 2015 for eligible studies. We included ten studies that analyzed the effects of RASB treatment on the incidence of cognitive decline or dementia.
  
  
  RESULTS
  We found that the use of RASB was associated with a reduced risk of dementia (RR, 0.84; 95% CI, 0.76-0.92), when randomized trials and observational trials were considered together. Meanwhile, regardless of the drug class, both the angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) were shown to effectively decrease the incidence rate of dementia (RR, 0.89; 95% CI, 0.82-0.96; RR, 0.79; 95% CI, 0.64-0.94, respectively). Furthermore, indirect comparison between ACEIs and ARBs revealed no correlation in incident dementia (RR, 0.89, 95% CI 0.72-1.09, p=0.26). However, centrally acting ACEIs (CACEIs) protected against the occurrence of dementia (RR, 0.94; 95% CI, 0.91-0.97); on the contrary, peripheral ACEIs (PACEIs) increased the risk of dementia (RR, 1.20; 95% CI, 1.00-1.43). In an analysis of cognitive decline, CACEIs use was shown to decrease the risk of cognitive decline (RR, 0.92; 95% CI, 0.83-1.00); however, ARBs use had no significant association with the risk of cognitive decline (RR, 0.98; 95% CI, 0.90-1.05).
  
  
  CONCLUSIONS
  RASB antihypertensive drugs may be potential treatments for reducing the incidence of dementia, but ARBs use is likely to be analogous to ACEIs. The association of dementia with CACEIs and PACEIs may be opposite, with CACEIs being effective. Meanwhile, the benefit differing according to drug classes for cognitive decline, CACEIs use, rather than ARBs use, is likely to play protective role in cognitive decline.
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhuang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China. Electronic address: xingchengming@medmail.com.cn.
authors.forename: Cheng-Ming
authors.initials: CM
authors.lastname: Xing
mesh_terms: D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D060825:Cognitive Dysfunction / Q000517:prevention & control*; D003704:Dementia / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012307:Risk Factors
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents
keywords: Angiotensin receptor blockers; Angiotensin-converting enzyme inhibitors; Cognitive decline; Dementia; Meta-analysis; Renin-angiotensin system blockade