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THURSDAY, June 26, 2003 (HealthDayNews) -- If you want to save money in screenings for those most likely to have a heart attack or stroke in the next few years, a blood test at age 50 seems to be the most cost-effective method, a British study says.
Testing everyone for high levels of blood cholesterol is an expensive proposition, says a report in the June 28 British Medical Journal, maybe too expensive for society to afford.
Money can be saved by reserving those tests for people at high risk because of other factors, so a group led by Dr. Sarah Wilson, a senior research fellow at the William Harvey Research Institute in London ran a study on 6,307 people ages 30 to 74 to see which of four criteria works best.
This was a purely hypothetical study, not one of those trials in which people are followed for years to see who develops heart disease. Instead, the researchers picked out those people who met the criteria of the widely accepted Framingham 10-year coronary heart disease risk equation, based on results of the classic Framingham Heart Study in the United States, which has been found to be extremely accurate in predicting risk.
All the participants were first tested to see which ones met the Framingham criteria. Then, knowing those who were at high risk, the researchers used a screen within a screen, four different times.
First they applied the guidelines of the British National Health Service to pick out those most likely to need a cholesterol test. Those guidelines selected 43.4 percent of the people in the group as needing a cholesterol test; that test then identified 81.2 percent of those who meet the Framingham criteria for a 15 percent greater likelihood of a coronary incident in those 10 years.
A second preliminary screen was the Sheffield table, a British set of rules. It selected 73.1 percent of the group as needing a cholesterol test; that test identified better than 99 percent of those who met the Framingham criteria for high risk.
The worst results came from using fixed values of blood cholesterol; it required blood tests for only 17.8 percent of the group, with a cholesterol test showing 75.9 percent of them meeting the Framingham high-risk criteria.
Using age 50 as the criterion proved that tests were required for 46.3 percent of the group and identified 92.8 percent of them as high-risk people -- not as good as the Sheffield criterion, but almost as good and a lot less expensive because fewer tests are needed.
The age-50 screen "has been shown to be a simple and efficient method of identifying those at risk of heart disease and enables limited resources to be targeted to those in greatest need," Wilson says. "In addition, it ensures accessibility to care across all ethnic groups, creeds, and social classes."
In the real world, those people will be followed for years "to test the predictive performance of the Framingham equation," she adds.
It's an interesting venture into the hypothetical, says Dr. Richard Pasternak, director of preventive cardiology at Massachusetts General Hospital and a spokesman for the American Heart Association (AHA), but one that is highly unlikely to be put into action here, or anywhere else.
"We have such inexpensive ways to screen patients, given all the things that are done these days, that I can't see why any country would not consider testing everyone who reaches adulthood," he adds.
And by leaving out younger people, the method might be pound-foolish, Pasternak says. "If we identify those young adults who have premature heart disease, the progression of the disease might be halted."
Pasternak stands by the AHA's updated recommendations, which call for thorough risk factor assessment at age 20 and comprehensive testing every five years for those 40 and over who have at least two risk factors, such as smoking or diabetes.