New England Journal of Medicine MAY 01, 2008

Treatment of Hypertension in Patients 80 Years of Age or Older

Beckett NS, Peters R, Fletcher AE, et al. (HYVET Investigators)

Bottom Line

In patients aged 80 years or older with hypertension, active antihypertensive treatment with indapamide (with optional perindopril) significantly reduced the rates of stroke and total mortality compared to placebo.

Key Findings

1. The primary endpoint of fatal or nonfatal stroke was reduced by 30% in the active treatment group compared to the placebo group (Hazard Ratio [HR] 0.70; 95% Confidence Interval [CI] 0.49–1.01; p=0.055, which did not meet the prespecified significance level for the primary outcome).

2. All-cause mortality was significantly reduced by 21% in the active treatment group (HR 0.79; 95% CI 0.65–0.95; p=0.02).

3. The rate of fatal strokes was significantly reduced by 39% (HR 0.61; 95% CI 0.38–0.99; p=0.046).

4. The rate of heart failure was significantly reduced by 64% in the active treatment group (HR 0.36; 95% CI 0.22–0.58; p<0.001).

5. Active treatment was well-tolerated, with a significantly lower incidence of serious adverse events reported in the active treatment group (18.5%) compared to the placebo group (23.4%; p=0.001).

Study Design

Design

RCT

Double-Blind

Sample

3,845

Patients

Duration

1.8 yr

Median

Setting

Multicenter, international

Population Patients aged 80 years or older with a sustained systolic blood pressure of 160 to 199 mm Hg.

Intervention Indapamide sustained release (1.5 mg) with the addition of perindopril (2 mg or 4 mg) if needed to reach a target blood pressure of <150/80 mm Hg.

Comparator Matching placebo

Outcome Rate of fatal or nonfatal stroke

Study Limitations

• The study was terminated early due to significant benefits in secondary outcomes (mortality), which may have potentially led to an overestimation of treatment effect.

• The primary outcome (stroke) narrowly missed statistical significance at the conventional 0.05 level (p=0.055).

• The median follow-up period was relatively short (1.8 years), leaving questions regarding the long-term safety and efficacy beyond this duration.

• The study population was selected based on relatively high baseline blood pressure and excluded those with dementia or those requiring daily nursing care, potentially limiting generalizability to the most frail or institutionalized elderly individuals.

Clinical Significance

HYVET provided pivotal evidence that treating hypertension in individuals aged 80 and older is not only safe but also confers a substantial reduction in cardiovascular morbidity and total mortality, effectively ending the clinical uncertainty regarding the benefit-risk ratio in this vulnerable population and shaping international hypertension management guidelines.

Historical Context

Prior to HYVET, the treatment of hypertension in the very elderly was controversial, as many previous cardiovascular outcome trials excluded patients over 80, and meta-analyses of existing data had raised concerns that aggressive lowering of blood pressure might increase all-cause mortality in this age group due to potential adverse effects or frailty.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

What is the primary mechanism of action of indapamide, and why is its classification as a 'thiazide-like' diuretic clinically significant compared to standard thiazides?

Key Response

Indapamide inhibits the sodium-chloride cotransporter in the distal convoluted tubule. It is 'thiazide-like' because it lacks the benzothiadiazine core but shares the mechanism. Clinically, indapamide has a longer half-life and demonstrates additional vasodilatory effects, making it particularly effective for blood pressure reduction and stroke prevention, as evidenced in the HYVET trial.

Resident

How should the HYVET trial's target blood pressure of <150/80 mmHg be reconciled with more recent SPRINT data suggesting lower targets in patients over 75?

Key Response

HYVET established a clear benefit for treating the 'very elderly' to a target of <150/80 mmHg, significantly reducing stroke and mortality. While SPRINT suggested further benefit at <120 mmHg, residents must differentiate the measurement techniques; SPRINT used unattended automated office BP, which usually reads lower than standard office measurements used in HYVET. Clinical application requires balancing aggressive targets against the risk of falls and orthostatic hypotension.

Fellow

Considering the HYVET-COG substudy findings, why might the trial have failed to show a statistically significant reduction in incident dementia despite a clear reduction in stroke?

Key Response

The HYVET-COG study showed a non-significant 14% reduction in dementia. This may be due to the trial being stopped early for mortality benefit, which reduced the person-years of follow-up required to observe slow-onset cognitive decline. Additionally, the 'healthy survivor' effect and the complexity of multi-factorial dementia in the very elderly make it difficult for blood pressure intervention alone to show significance in a relatively short timeframe.

Attending

How did the HYVET trial shift the paradigm regarding the 'J-curve' phenomenon in octogenarians, and how do you incorporate this into teaching regarding geriatric hypertension?

Key Response

Prior to HYVET, there was significant concern that lower diastolic pressures would increase coronary events (the J-curve). HYVET provided robust evidence that active treatment to 150/80 mmHg reduced total mortality by 21% and heart failure by 64%, effectively debunking the idea that hypertension is a necessary physiological adaptation of aging. Teaching should emphasize that 'age is not a contraindication' to treatment but requires careful titration.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

HYVET utilized a double-blind, placebo-controlled design in an extremely elderly population; evaluate the ethical and statistical implications of the 'stopping rules' applied to this trial.

Key Response

The trial was stopped early because the mortality benefit crossed a pre-defined threshold. Statistically, stopping early can lead to an overestimation of treatment effects (the 'winner's curse') and leave secondary outcomes (like dementia or long-term safety) underpowered. Ethically, once a mortality benefit is established, continuing the placebo arm is untenable, but researchers must then use modeling to estimate the magnitude of effect that would have occurred had the trial reached its planned completion.

Journal Editor

What are the potential biases introduced by the HYVET study's exclusion criteria, specifically regarding the exclusion of patients with dementia or those requiring nursing care?

Key Response

By excluding the most frail—those with dementia or institutionalized—the trial likely enrolled a 'robust' subset of the 80+ population. This 'healthy volunteer bias' may limit the external validity (generalizability) of the results to the average geriatric patient seen in practice, who often presents with the very comorbidities HYVET excluded, potentially leading to an underestimation of adverse events in the real world.

Guideline Committee

How do the HYVET results influence the strength of recommendation for initiating therapy in adults over 80 with Grade 1 hypertension compared to current ESC/ESH or ACC/AHA guidelines?

Key Response

The ACC/AHA guidelines (2017) and ESC/ESH guidelines (2018/2023) cite HYVET as foundational evidence. While HYVET targeted <150/80 mmHg, current guidelines have shifted lower (e.g., <140/90 or even <130/80 if tolerated). However, HYVET remains the benchmark for 'Level A' evidence that treatment should be initiated in the very elderly even at higher thresholds (SBP >160 mmHg), emphasizing that the reduction in heart failure and stroke outweighs the risk of polypharmacy in this demographic.

Clinical Landscape

Noteworthy Related Trials

1997

Syst-Eur Trial

n = 4,695 · NEJM

Tested

Nitrendipine-based antihypertensive regimen

Population

Older patients with isolated systolic hypertension

Comparator

Placebo

Endpoint

Fatal and nonfatal stroke

Key result: Active treatment reduced the incidence of stroke by 42% and all cardiovascular events by 31%.

2003

SCOPE Trial

n = 4,964 · Lancet

Tested

Candesartan-based regimen

Population

Patients aged 70 to 89 with mild hypertension

Comparator

Placebo-based control group

Endpoint

Major cardiovascular events

Key result: Candesartan treatment resulted in a significant reduction in nonfatal strokes, though the effect on the primary composite endpoint was not statistically significant.

2015

SPRINT Trial

n = 9,361 · NEJM

Tested

Intensive systolic blood pressure control (<120 mmHg)

Population

Adults age 50 and older at high cardiovascular risk

Comparator

Standard systolic blood pressure control (<140 mmHg)

Endpoint

Composite of myocardial infarction, acute coronary syndromes, stroke, acute decompensated heart failure, or death from cardiovascular causes

Key result: Intensive treatment significantly reduced rates of major cardiovascular events and all-cause mortality compared to standard treatment.

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