Editor—Wilson et al assert that measuring cholesterol concentration only in people of at least 50 efficiently identifies those at high risk of coronary heart disease.1 This oversimplification results from a study with important defects.
Firstly, Wilson et al determined absolute risk of coronary heart disease by using the Sheffield tables and the underlying Framingham algorithm. However, in the German prospective cardiovascular Münster (PROCAM) study and the Augsburg cohort of the World Health Organization's monitoring trends and determinants in cardiovascular disease (MONICA) study, Framingham overestimated coronary risk about twofold.2 Even allowing for the higher incidence of coronary heart disease in Britain compared with Germany,3 Wilson et al should have calculated risk by using either a British algorithm or a corrected Framingham formula.
Secondly, Wilson et al considered men and women together, even though risk of coronary heart disease in women is two to four times less than in age matched men aged up to about the age of 60. This error dilutes male risk of coronary heart disease, which is substantial even in early middle age. In the PROCAM study, for example, no fewer than 8% of men under 50 had a 10 year risk of coronary heart disease of more than 15% with the Framingham formula.
A particular aim in preventing coronary heart disease is to stop the early events that produce an especially high burden of morbidity and cost. Moreover, since the risk increases sharply with age, patients at borderline risk below the age of 50 require attention if they are not to proceed inexorably into a high risk group. Limiting cholesterol measurements to the over 50s will increase costs and disease burden.
Competing interests: None declared.
References
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