Affiliations: [a] Department of Geriatrics, University Paris- Descartes, Broca Hospital, AP-HP, France | [b] Hôpital Broca, Service de Gériatrie du Professeur AS Rigaud, 54-56 rue Pascal, 75013 Paris, France | Center for Alzheimer's Research, Banner Sun Health Research Institute, Sun City, AZ, USA
Correspondence:
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Correspondence to: Emmanuelle Duron, M.D., Department of Geriatrics, University Paris- Descartes, Broca Hospital, AP-HP, France; Hôpital Broca, Service de Gériatrie du Professeur AS Rigaud, 54-56 rue Pascal, 75013 Paris, France. Tel.: +33 144083503; Fax: +33 144083510; E-mail: emmanuelle.duron@brc.aphp.fr.
Abstract: Chronic hypertension is associated with an increased risk of both vascular dementia and Alzheimer's disease (AD). In this context, the role of anti-hypertensive therapy for the prevention and delay of cognitive decline and dementia is of central importance. Most longitudinal studies have shown a significant inverse association between anti-hypertensive therapies and dementia incidence and for some of these, particularly in AD. Seven randomized, double blind placebo-controlled trials have evaluated the benefit of antihypertensive treatments on cognition. Three of them found positive results in term of prevention of dementia (SYST-EUR) or cognitive decline (PROGRESS, HOPE). Others disclosed non-significant results (MRC, SHEP, SCOPE, HYVET-COG). This discrepancy emphasizes the difficulty to perform such trials: the follow-up has to be long enough to disclose a benefit, a large number of patients is needed for these studies, and because of ethical reasons some anti-hypertensive treatments are often prescribed in the placebo group. Results of the two more recent meta-analyses are inconsistent, possibly due to methodological issues. Antihypertensive treatments could be beneficial to cognitive function by lowering blood pressure and/or by specific neuroprotective effect. Three main antihypertensive subclasses have been associated with a beneficial effect on cognitive function beyond blood pressure reduction (calcium channel blockers, angiotensin converting enzyme inhibitor, angiotensin-AT1-receptor-blockers). Further long-term randomized trials, designed especially to assess a link between antihypertensive therapy and cognitive decline or dementia are therefore needed with cognition as the primary outcome. A low blood pressure threshold that could be deleterious for cognitive function should also be determined.
