Researchers assessed the accuracy of the Framingham risk equation for coronary heart disease in 6,643 British men aged 40-59 years. All men were initially free of heart disease.
Over a 10 year period, 2.8% of men died from coronary heart disease compared with 4.1% predicted - a overestimation of 47%. A fatal or non-fatal coronary heart disease event occurred in 10.2% of the men compared with 16% predicted - an overestimation of 57%.
The degree of over-prediction was similar at all risk levels, so that overestimation of absolute risk was greatest for people at highest risk. However, a simple adjustment by the authors improved the level of accuracy.
These finding have important implications, say the authors. For instance, an overestimated assessment of coronary heart disease risk will undermine a patient's ability to make an informed choice about starting preventive treatment, may cause unnecessary anxiety, and may affect life insurance premiums.