Blood pressure lowering and prevention of dementia: an individual patient data meta-analysis

Ruth Peters, Ying Xu, Oisin Fitzgerald, Htein Linn Aung, Nigel Beckett, Christopher Bulpitt, John Chalmers, F. Forette, Jessica Gong, Katie Harris, Peter Humburg, Fiona E. Matthews, Jan A. Staessen, L. Thijs, C. Tzourio, J. Warwick, Mark Woodward, Craig S. Anderson, Dementia rIsk REduCTion (DIRECT) collaboration

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

Aims
Observational studies indicate U-shaped associations of blood pressure (BP) and incident dementia in older age, but randomized controlled trials of BP-lowering treatment show mixed results on this outcome in hypertensive patients. A pooled individual participant data analysis of five seminal randomized double-blind placebo-controlled trials was undertaken to better define the effects of BP-lowering treatment for the prevention of dementia.

Methods and results
Multilevel logistic regression was used to evaluate the treatment effect on incident dementia. Effect modification was assessed for key population characteristics including age, baseline systolic BP, sex, and presence of prior stroke. Mediation analysis was used to quantify the contribution of trial medication and changes in systolic and diastolic BP on risk of dementia. The total sample included 28 008 individuals recruited from 20 countries. After a median follow-up of 4.3 years, there were 861 cases of incident dementia. Multilevel logistic regression reported an adjusted odds ratio 0.87 (95% confidence interval: 0.75, 0.99) in favour of antihypertensive treatment reducing risk of incident dementia with a mean BP lowering of 10/4 mmHg. Further multinomial regression taking account of death as a competing risk found similar results. There was no effect modification by age or sex. Mediation analysis confirmed the greater fall in BP in the actively treated group was associated with a greater reduction in dementia risk.

Conclusion
The first single-stage individual patient data meta-analysis from randomized double-blind placebo-controlled clinical trials provides evidence to support benefits of antihypertensive treatment in late-mid and later life to lower the risk of dementia. Questions remain as to the potential for additional BP lowering in those with already well-controlled hypertension and of antihypertensive treatment commenced earlier in the life-course to reduce the long-term risk of dementia.

Classification of evidence
Class I evidence in favour of antihypertensive treatment reducing risk of incident dementia compared with placebo.
Original languageEnglish
Pages (from-to)4980-4990
Number of pages11
JournalEuropean Heart journal
Volume43
Issue number48
DOIs
Publication statusPublished - 21 Dec 2022
Externally publishedYes

Keywords

  • Hypertension
  • Blood pressure
  • Cognition
  • Dementia
  • Meta-analysis
  • Clinical trials

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