CHICAGO - April 4, 2008 - Treatment of high blood pressure results in improved outcomes for patients over 80 years of age, according to the Hypertension in the Very Elderly (HYVET) trial, reported here at the American College of Cardiology (ACC) 57th Annual Scientific Session.
The study was the largest randomised, controlled trial assessing the benefit-to-risk ratio of treating hypertensive patients aged 80 years and older. The results showed that lowering blood pressure of elderly patients could cut their total mortality by one fifth and their rate of cardiovascular events by one third.
The findings have the potential to affect the treatment and impact the health outcomes of millions of individuals, the researchers said.
"These results will have important implications for the generation of future guidelines and mean that very elderly individuals with sustained systolic blood pressures of 160 mm Hg or more should now be appropriately assessed and treated in accordance with the new findings," said lead author Nigel S. Beckett, MB, Research Fellow and Trial Coordinator, Care of the Elderly Group, Imperial College London, London, United Kingdom.
The HYVET trial was a randomised, double-blind, placebo-controlled study involving patients aged 80 or older.
Researchers randomised 1,912 patients to placebo and 1,933 patients to active treatment with indapamide sustained release 1.5 mg with the addition of oral perindopril 2 to 4 mg once daily as needed to reach a target blood pressure of 150/80 mm Hg. Mean age of the entire cohort was 84 years, and systolic blood pressure was 160 to 199 mm Hg.
After 4 years of follow-up, all-cause mortality was 23% in patients taking placebo and 18% in the active treatment group, Dr. Beckett said. That represents a 21% relative risk reduction, which achieved statistical significance at the P = .019 level.
Stroke mortality was reduced by 39% in the active-treatment patients (P = .046). All strokes were reduced by 30% in the active-treatment group (P = .06). Fatal and nonfatal heart failure was reduced by 64% in the active-treatment group (P < .001). There was a 34% reduction in cardiovascular events (P < .001).
The benefits were apparent within the first year of follow-up. The average follow-up was just over 2 years, by which time 20% of the placebo subjects and 48% of those taking medication had achieved the target blood pressure of 150/80 mm Hg.
In July 2007, the HYVET steering committee accepted the recommendations of the independent Data-Monitoring and Ethics Committees to stop the trial early. This was based on the results from the second planned interim analysis that showed a significant reduction in the primary endpoint and total mortality.
While elevated blood pressure levels are common among very elderly patients, the benefit-to-risk ratio for treating such patients was not established prior to this study, Dr. Beckett said.
"An unexpected finding of our trial is the reduction in the risk of death from any cause with active treatment, making HYVET one of the few individual studies of hypertension showing benefits of blood pressure reduction on mortality," Dr. Beckett said in an oral late-breaker session on March 31.
"Our results clearly show that many patients aged 80 and over could benefit greatly from treatment. Populations are living longer and we have growing numbers of people living well into their 80s and beyond," he said. Results of HYVET are unequivocal, he added.
The results of the study should not be generalised to apply to individuals in their 90s or older, Dr. Beckett said at a press briefing. "There are diminishing returns in the benefit-to-risk ratio in people in their 90s or even 100s," he explained.
The HYVET trial was published simultaneously at www.nejm.org on March 31, 2008, (doi:10.1056/NEJMoa0801369) and was sponsored by Imperial College London.