The pooled results of four major international clinical trials involving over 48,000 people, in which over 25,000 were treated with aspirin, were subjected to detailed analysis. Aspirin is well known to reduce the risk of heart attacks in stroke in those who have already suffered these problems.
The results showed that aspirin cut the risk of first heart attacks by almost a third. But it also increased the risk of bleeding complications by almost 70%.
The researchers therefore argue that, in treatment, it is important to identify how likely a person is to have a heart attack. If the risk of a heart attack is calculated as being moderately high, at 15% over 10 years, taking 75 mg of aspirin daily is worthwhile, the data indicate.
Except in people with ulcers or high blood pressure that is not being treated, the chance of preventing a heart attack far outweighs any possible harm.
In people at moderate risk - between 5 and 15% - the benefits and disadvantages cancel each other out, so the authors conclude that taking aspirin is probably worthwhile.
|In subjects with low risk of heart attack, the side-effects of taking aspirin outweigh the advantages.|
However those at low risk, with a 5% chance of having a heart attack within the next 10 years, the side-effects, such as bleeding from the stomach, are likely to outweigh any benefit.
Heart disease risk can only be calculated using a set of specially devised tables, taking into account all the possible risk factors, such as smoking, family history, and cholesterol levels.
The difficulty is that people do not often know their true level of heart disease risk, and may simply decide to treat themselves, conclude the authors.