LONDON -- People at high risk of heart attack or stroke -- not just patients who have already been stricken -- should be taking aspirin, but the dosage could be about half of what is now prescribed, according to major new research.
The study also concluded that the aspirin can help a wider range of people with potential heart trouble -- those suffering from risky conditions such as diabetes, chest pain, irregular heart beat and diseased leg arteries.
Aspirin has long been the cornerstone of blood thinning treatment for people who have had a heart attack or stroke, but it is not normally used by those who suffer potential precursor ailments.
The research found that aspirin reduced the risk of heart attack , stroke, or death from those events by 25 percent even in patients who had not suffered a heart attack or stroke.
The findings come from an analysis that combines evidence accumulated over the years on the effectiveness of aspirin and its alternatives in staving off heart trouble. Coordinated by scientists at Oxford University in England, it encompassed 287 studies involving 200,000 people.
The study's most crucial advance is in defining the appropriate dose of aspirin for long-term therapy, said Dr. Eric Topol, cardiology chief at the Cleveland Clinic which was not involved in the analysis.
"That's a big thing. Before this analysis we weren't sure what the dose was at all," Topol said. He said doses of 325 milligrams were readily available, so they were used out of convenience.
"But now I think we've zeroed in on a range of 80 to 160," he said.
Most doctors and heart specialists prescribe 325 milligrams of aspirin -- the same as a maximum strength adult aspirin tablet -- per day when applying it as a blood thinner.
The latest analysis shows that between 75 milligrams and 150 milligrams works just as well, with less chance of internal bleeding. In the United States, a baby aspirin tablet, also available as low-dose adult aspirin, contains 81 milligrams.
"There are two problems," Topol concluded "Doctors are giving too much or they are not giving any at all. We have a lot of work to do now to get all the patients treated and at the right dose.