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| English: Myocardial infarction ECG (Photo credit: Wikipedia) |
Background
The prediction of the absolute risk of coronary heart disease (CHD) is
commonly based on risk prediction equations that originate from the Framingham
Heart Study. However, differences in population risk levels compromise the external
validity of these risk functions.
Setting and study population
Participants aged 35–64 years from the MONICA Augsburg (2861 men and 2925 women) and the PROCAM (5527 men and 3155 women) cohorts were followed-up with regard to incident non-fatal myocardial infarction (MI)and fatal coronary events. For each participant, the predicted absolute risk of fatal plus non-fatal events was derived using Framingham risk equations. Predicted and
actually observed risks were compared.
Results
The two cohorts were similar in their baseline characteristics. Coronary risk
predicted by the Framingham risk function substantially exceeded the risk actually
observed in the German cohorts, irrespective of gender. The difference between
predicted and observed absolute CHD risk increased with age while the ratio of
predicted over observed risk remained constant at about a value of 2. Taking
potentials for underascertainment in the German cohorts due to unrecognised MI and
sudden deaths into account, the residual magnitude of risk overestimation by the
Framingham risk function is probably at least 50%.
Conclusions
Local guidelines for the management of patients with risk factors need to
correct for this overestimation to avoid inadequate initiation of treatment and
inflation of costs in primary prevention. Similar studies should be conducted in other
populations with the aim of defining appropriate factors that calibrate absolute risk
predictions to local population levels of CHD risk.
