Pharmacological Blood Pressure Reduction Effective in All Age Groups

Kazem Rahimi, PhD

A new study challenged the uncertainty of the effects of pharmacological blood-pressure-lowering on cardiovascular outcomes in individuals aged 70 years and older, concluding that age-related blood-pressure thresholds should be removed when considering pharmacological blood pressure reduction methods.

The data were presented at the European Society of Cardiology (ESC) 2021 Congress.

Increased blood pressure has been an established risk factor for cardiovascular morbidity and mortality, with antihypertensive medications playing an essential role in cardiovascular protection and management.

Despite this, a looming uncertainty regarding blood-pressure-lowering pharmacotherapy had always been whether treatment should be initiated and/or continued in older age.

Conflicting evidence regarding blood pressure levels in older patients existed, with some studies noting increased risk of cardiovascular event rates due to low or high blood pressure levels.

For this study, investigators led by Kazem Rahimi, PhD, Deputy Director of the George Centre for Healthcare Innovation, University of Oxford, investigated the stratified effects of pharmacological blood-pressure-lowering treatment on the risk of major cardiovascular events and death across age, systolic, and diastolic blood pressure categories at baseline.

The Study

Via the third cycle of the Blood Pressure Lowering Treatment Trialists' Collaboration (BPLTTC), the team had access to individual participant-level data of over 350,000 randomly assigned patients with 22,000 patients aged 80 years and older.

Overall, 51 trials comprising 358,707 participants were included in the analysis.

The investigators then performed a 1-stage, individual participant-level data, meta-analysis using stratified Cox proportional hazard models.

To test whether treatment effects varied across prespecified subgroups of age categories and systolic and diastolic blood pressure at baseline, we used likelihood-ratio tests for interactions that compared models with and without interactions between treatment effect and age or blood pressure categories.

The primary outcome was defined as a composite of fatal or non-fatal stroke, fatal or non-fatal myocardial infarction or ischaemic heart disease, or heart failure causing death or requiring hospital admission. The secondary outcomes were all-cause death and the components of the primary outcome.

The Findings

Rahimi and colleagues recorded no reports of heart failure outcome in 6 (12%) trials, no cardiovascular death outcomes in 5 (10%) trials, and no stroke and ischaemic heart disease outcomes in 1 (2%) trial.

Though incidences increased with increasing age, in all age groups the event rates were lower in the intervention group than the comparator group.

However, the confidence limit was widest in the group of individuals aged 85 years or older at baseline.

Further analysis showed no evidence of any heterogeneous treatment effect by categories of systolic blood pressure at baseline on the risk of major cardiovascular events in any of the age groups.

Overall, pharmacological blood pressure reduction was effective across a wide range of ages with no evidence to suggest that relative risk reductions for prevention of major cardiovascular events vary by baseline systolic or diastolic blood pressure levels down to less than 120/70 mm Hg.

Rahimi and colleagues believed their study “closed the gap” in evidence for age-specific treatment effects on major cardiovascular outcomes.

“Although clinical decision making for initiation and continuation of pharmacological blood-pressure-lowering will continue to be based on harm-benefit trade-offs for any individual, our study does not support the common belief that such trade-offs justify the overemphasis of several clinical practice guidelines on an individual's age or starting blood pressure,” the team wrote.

The study, “Age-stratified and blood-pressure-stratified effects of blood-pressure-lowering pharmacotherapy for the prevention of cardiovascular disease and death: an individual participant-level data meta-analysis,” was published in The Lancet.