London: An international trial looking at the benefits of giving blood-pressure lowering medication to elderly patients has stopped early, after researchers observed significant reductions in overall mortality in those receiving treatment.

The 3,845 patient Hypertension in the Very Elderly Trial (HYVET) is the largest ever clinical trial to look at the effects of lowering blood pressure solely in those aged 80 and over. Preliminary results of the trial, which is coordinated by scientists from Imperial College London, suggest that lowering blood pressure significantly reduces both stroke and mortality in the over-80s.

A number of earlier trials had demonstrated that reducing blood pressure in the under-80s reduces stroke and cardiovascular events. However, previous smaller and inconclusive studies also suggested that whilst lowering blood pressure in those aged 80 or over reduced the number of strokes, it did not reduce, and even increased, total mortality.

Patients with high blood pressure from across the world were randomised for the double-blind, placebo-controlled trial, which began in 2001. Patients were given either the placebo or a low dose diuretic (indapamide 1.5mg SR), and an additional ACE inhibitor (perindopril), in tablet form once a day.

Emeritus Professor Chris Bulpitt, HYVET Principal Investigator from the Care of the Elderly Department at Imperial College London, said: “It was not clear prior to our study whether the over-80s would benefit from blood pressure lowering medication in the same way as younger people.

Our results are great news for people in this age group because they suggest that where they have high blood pressure, such treatment can cut their chances of dying as well as stroke.”

The Steering Committee of HYVET accepted on 12th July 2007 the recommendation of its Data Safety Monitoring Board that the trial should be stopped.

Definitive figures will not be available until all the data has been collected. Results will then be published in the peer reviewed scientific press.

Over the next few months all HYVET patients will be seen for a final visit, where all patients on trial medication will be offered the option of switching to active indapamide 1.5 mg SR based antihypertensive treatment. Prior to their final visit, all patients are advised to stay on their existing drugs until they see their trial physician.

HYVET was co-ordinated by scientists from Imperial College London, working with colleagues around the world. The main trial was funded by both the British Heart Foundation and by the Institut de Recherches Internationales Servier.

1. About stroke and high blood pressure

* Stroke is the third most common cause of death in the England and Wales. In 2004, 11% of deaths amongst those aged 75-84, and 14% of deaths amongst those aged over 85 were due to stroke, according to the Office of National Statistics.

* In the UK about 150,000 people suffer a stroke each year, the equivalent of 1 every 4 minutes.

* About one third of stroke patients die within 6 months of the event, the majority occurring in the first month.

* Disability after stroke is the most important single cause of severe disability of people living in their own homes.

* There are 2 types of stroke:

a. Haemorrhagic – caused by blood leaking into brain tissue from a
blood vessel within the brain
b. Ischeamic – caused by a clot occluding a blood vessel, resulting in
loss of blood supply to a part of the brain and subsequent damage to brain tissue.

High blood pressure increases the chance of both a blood vessel leaking or rupturing, and of a clot forming within a blood vessel. High blood pressure increases the likelihood of damage to the lining of the blood vessel, which in turn leads to an increased chance of spontaneous clot formation within the blood vessel.

* The over 80s are the fastest growing group in the population worldwide – in the UK currently they account for 4% of the total population and this is expected to rise to over 11% by 2050.

* The risk of stroke increases with age, with some estimates suggesting that the risk doubles every decade after a person reaches 55 years of age

* In the UK approximately 4% of the total National Health Service budget is spent on stroke services each year.