Is the Association Between Blood Pressure and Mortality in Older Adults Different With Frailty?

A Systematic Review and Meta-analysis

Oliver M Todd; Chris Wilkinson; Matthew Hale; Nee Ling Wong; Marlous Hall; James P Sheppard; Richard J McManus; Kenneth Rockwood; John Young; Chris P Gale; Andrew Clegg

Disclosures

Age Ageing. 2019;48(5):627-635. 

In This Article

Abstract and Introduction

Abstract

Objective: to investigate whether the association between blood pressure and clinical outcomes is different in older adults with and without frailty, using observational studies.

Methods: MEDLINE, EMBASE and CINAHL were searched from 1st January 2000 to 13th June 2018. PROSPERO CRD42017081635. We included all observational studies reporting clinical outcomes in older adults with an average age over 65 years living in the community with and without treatment that measured blood pressure and frailty using validated methods. Two independent reviewers evaluated study quality and risk of bias using the ROBANS tool. We used generic inverse variance modelling to pool risks of all-cause mortality adjusted for age and sex.

Results: nine observational studies involving 21,906 older adults were included, comparing all-cause mortality over a mean of six years. Fixed effects meta-analysis of six studies demonstrated that in people with frailty, there was no mortality difference associated with systolic blood pressure <140 mm Hg compared to systolic blood pressure >140 mm Hg (HR 1.02, 95% CI 0.90 to 1.16). In the absence of frailty, systolic blood pressure <140 mm Hg was associated with lower risk of death compared to systolic blood pressure >140 mm Hg (HR 0.86, 95% CI 0.77 to 0.96).

Conclusions: evidence from observational studies demonstrates no mortality difference for older people with frailty whose systolic blood pressure is <140 mm Hg, compared to those with a systolic blood pressure >140 mm Hg. Current evidence fails to capture the complexities of blood pressure measurement, and the association with non-fatal outcomes.

Introduction

Improvements in cardiovascular care and global demographic changes mean that people are now more typically living into later life with hypertension. By the age of 80, more than three quarters of adults will have been diagnosed with hypertension.[1] However, life course trajectories of systolic blood pressure demonstrate deceleration and eventual decline in later life.[2] The association of blood pressure and the proportional risk of vascular mortality reduces with age.[3] Furthermore, anti-hypertensive treatment in older people can be associated with harm: higher rates of electrolyte disturbance, acute kidney injury,[4] orthostatic hypotension, syncope and falls.[5] Evidence also indicates accelerated cognitive decline in patients with established mild cognitive impairment or dementia.[6]

Little guidance is available to help practitioners identify patients for whom a less intensive approach to blood pressure management is appropriate. There are good reasons to consider a person's frailty status when treating blood pressure. Frailty is better than chronological age in predicting all-cause mortality,[7] primary cardiac end-points,[8] and functional outcomes including disability, falls, and nursing home admissions.[9] People living with frailty can be especially prone to the adverse effects of medications.[10]

There is an absence of the necessary randomised control trial (RCT) evidence on which to base clinical guidelines for this patient group. Therefore, a summary of observational studies is necessary, albeit with the caveat that their interpretation must account for their higher risk of reverse causality and residual confounding. Criteria for treatment and thresholds for diagnosis of hypertension vary across countries and over time. We therefore conducted a systematic review and meta-analysis of observational studies including older people living with frailty in the community, with and without antihypertensive treatment, to investigate whether the observed relationship between blood pressure and relevant clinical outcomes is different in the context of frailty.

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