Validity of the Framingham point scores in the elderly: Results from the Rotterdam study

Background

The National Cholesterol Education Program recommends assessing 10-year risk of coronary heart disease (CHD) in individuals free of established CHD with the Framingham Point Scores (FPS). Individuals with a risk >20% are classified as high risk and are candidates for preventive intervention. We aimed to validate the FPS in a European population of elderly subjects.

Methods

Subjects free of established CHD at baseline were selected from the Rotterdam study, a population-based cohort of subjects 55 years or older in the Netherlands.

We studied calibration, discrimination (c-index), and the accuracy of high-risk classifications. Events consisted of fatal CHD and nonfatal myocardial infarction.

Results

Among 6795 subjects, 463 died because of CHD and 336 had nonfatal myocardial infarction. Predicted 10-year risk of CHD was on average well calibrated for women (9.9% observed vs 10.1% predicted) but showed substantial overestimation in men (14.3% observed vs 19.8% predicted), particularly with increasing age. This resulted in substantial number of false-positive classifications (specificity 70%) in men. In women, discrimination of the FPS was better than that in men (c-index 0.73 vs 0.63, respectively). However, because of the low baseline risk of CHD and limited discriminatory power, only 33% of all CHD events occurred in women classified as high risk.

Conclusions

The FPS need recalibration for elderly men with better incorporation of the effect of age. In elderly women, FPS perform reasonably well. However, maintaining the rational of the high-risk threshold requires better performing models for a population with low incidence of CHD.