title: Impact of renin-angiotensin system-targeting antihypertensive drugs on treatment of Alzheimer's disease: a meta-analysis.
abstract: OBJECTIVE
  The impacts of renin-angiotensin system (RAS)-targeting antihypertensive drugs on Alzheimer's disease (AD) remain controversial. We performed this meta-analysis to evaluate the precise value of RAS-targeting antihypertensive drugs in terms of attenuating incidence of AD and slowing down cognitive decline in patients with AD.
  
  
  METHODS
  A systematic literature search was conducted using PubMed, Embase, ScienceDirect and CBM (China Biology Medicine Disc) before September 2014. Studies analysing incidence of AD and cognitive changes in AD patients with RAS-targeting antihypertensive drugs were identified. The principal outcome measures were hazard ratios (HRs) for incidence of AD and standardised mean difference (SMD) for cognitive changes in AD patients. Pooled data were calculated using fixed or random effects models according to the heterogeneity.
  
  
  RESULTS
  In total, 12 studies involving 896,410 participants met our inclusion criteria. RAS-targeting antihypertensive drugs were significantly associated with a reduced incidence rate of AD (HR 0.81, 95% CI 0.72-0.92, p = 0.001). In subgroup analysis, both angiotensin renin blockers and angiotensin converting enzyme inhibitors were shown to effectively decrease the incidence rate of AD. In the analysis of cognitive changes, a slower rate of cognitive decline was observed in AD patients with RAS-targeting antihypertensive drug (SMD 0.30, 95% CI 0.09-0.50, p = 0.004), when randomised trials and observational trials were combined. However, analysis of randomised trials alone did not show the same result (SMD 0.20, 95% CI -0.10 to 0.50, p = 0.182).
  
  
  CONCLUSIONS
  Renin-angiotensin system-targeting antihypertensive drugs may be a potential treatment for reducing the incidence and progression of AD. Further studies on RAS-targeting antihypertensive drugs, especially large randomised clinical trials, should be conducted in the future.
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: R
authors.initials: R
authors.lastname: Ye
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: A
authors.initials: A
authors.lastname: Yao
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Neurology, Zhongnan Hospital, Wuhan University, Wuhan, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control; D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000453:epidemiology; D018450:Disease Progression; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D015994:Incidence; D012084:Renin-Angiotensin System / Q000187:drug effects* / Q000502:physiology
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents