The results of the study, announced today at the American College of Cardiology annual scientific session in Chicago, USA, and simultaneously published online in the Lancet, show that in a study of more than 10,305 people with high blood pressure and normal or only moderately raised levels of cholesterol, those receiving atorvastatin were 36 percent less likely to suffer from heart attacks, and 27 percent less likely to suffer from strokes.
Professor Peter Sever, from Imperial College London and St Mary's Hospital, London and ASCOT study co-chairman comments: "The results of this study are great news to those suffering from high blood pressure because the use of this drug significantly reduces the likelihood of either a stroke or heart attack, in addition to the benefits they will get from the drugs which lower their blood pressure."
Cholesterol in the blood is the major cause of atherosclerosis. It contributes to fatty deposits in the walls of the arteries leading to the heart and the brain. Eventually it blocks these key arteries, leading to either a heart attack or a stroke, respectively. In people with high blood pressure the risks of heart attack and stroke are increased, therefore a combined intervention to tackle both cholesterol and blood pressure should be doubly beneficial and likely to benefit a large number of "at risk" patients.
The results reported today come from the part of the ASCOT study, based in Denmark, Finland, Norway, Sweden, the UK and Ireland, that was stopped in October last year. Members of ASCOT's Data Safety Monitoring Board, who work independently of the trial investigators and are the only researchers permitted to look at the results of the five-year old trial while it is ongoing, reported that those receiving the atorvastatin were significantly less likely to suffer heart attacks or strokes. As a result this part of the trial was halted early, so those receiving the placebo in the control group could also benefit from the use of atorvastatin.
Professor Björn Dahlöf from the Sahlgrenska University Hospital, Östra, Sweden and ASCOT study co-chairman, adds: "At present, large numbers of people around the world are affected by high blood pressure, with only normal or slightly raised cholesterol, causing significant levels of ill health and mortality. This study shows that statins are effective, lowering cholesterol levels, and reducing the likelihood of heart attacks and strokes."
Patients were only eligible for the cholesterol lowering part of the trial if they had a blood cholesterol level of 6.5 mmol per litre or less - a significantly lower range of cholesterol levels than is usually treated by doctors. This part of the trial is specifically aimed to discover if a statin would confer additional protection against coronary heart disease in hypertensive patients with normal cholesterol levels. Patients with cholesterol levels more than 6.5 mmol/L were conventionally treated and were not randomised to the lipid lowering part of the study.
Statins are drugs designed to lower cholesterol levels by slowing down the production of cholesterol and by increasing the liver's ability to remove the cholesterol already in the blood.
The other primary objective of ASCOT is to compare a new treatment strategy for hypertension against an old one, and discover which is better at preventing heart attacks.
The new treatment is a calcium channel blocker (amlodipine), to which in the majority of patients the angiotensin converting enzyme inhibitor, perindopril, is added to achieve the goal blood pressure. The older treatment is a beta blocker (atenolol), to which in the majority of patients a diuretic, bendrofluazide, is added to achieve goal blood pressure.
By May 2000, 19,342 patients had been entered on the trial and randomly selected to receive one of the two blood pressure lowering strategies. Out of the trial total 10,305 patients with low cholesterol were also randomised to receive either placebo or atorvastatin.
About ASCOT Launched in 1997, the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) is an independent, investigator-led study aiming to evaluate different treatment strategies to prevent cardiovascular disease in hypertensive patients.
It is being conducted in over 700 general practices and regional medical centres across the UK, Ireland and the five Nordic countries, Sweden, Finland, Denmark, Norway and Iceland.
Number of patients on the ASCOT trial by country
Denmark (including Iceland) -- 1,567
Finland -- 2,382
Norway 2,226
Sweden 4,069
UK and Ireland 9,098
TOTAL 19,342
With over 19,000 patients across the UK, Ireland and Scandinavia, ASCOT is the largest European based prospective, randomised hypertension trial ever to be conducted.
It is jointly coordinated by Imperial College London (Cardiovascular Studies Unit, Department of Clinical Pharmacology, St Marys Hospital, London) and Scandinavian Coordinating Center (Scandinavian CRI AB), Göteborg, Sweden.
ASCOT web site: www.ascotstudy.org
Journal
The Lancet