Subjects with molecularly defined familial hypercholesterolemia or familial defective apoB-100 are not being adequately treated

Abstract

Objectives: To study whether subjects with a molecular genetic diagnosis of familial hypercholesterolemia (FH) or familial defective apoB-100 (FDB) are being adequately treated.

Design: A questionnaire regarding medical history was sent to 2611 subjects who had been provided with a molecular genetic diagnosis of FH or FDB, and a blood sample was obtained for lipid measurements.

Results: 956 (36.6%) of the 2611 subjects participated. The mean age for starting lipid-lowering therapy was 33.4 (±12.1) years. Among those below 18 years of age, only 20.4% were on lipid-lowering drugs, whereas 89.1% of those aged 18 and above were on lipid-lowering drugs. The mean levels of total serum cholesterol and LDL-cholesterol were 5.7 (±1.5) mmol/l and 3.9 (±1.3) mmol/l, respectively. Among those who were on lipid-lowering drugs, 29.0% and 12.2% had levels of LDL cholesterol below 3.0 mmol/l and 2.6 mmol/l, respectively. Only 47.3% of the 956 subjects were considered as being adequately treated largely due to a failure to titrate their drug regimens. From the use of cholesterol-years score, lipid-lowering therapy must start before the age of 20 in order to prevent the subjects from contracting premature coronary heart disease.

Conclusion: The majority of FH/FDB subjects are being diagnosed late in life and are not being adequately treated. In order to prevent them from contracting premature coronary heart disease, it is key that levels of LDL cholesterol are normalized from a young age and that sufficient doses of lipid-lowering drugs are being used.

Figure 1. Cholesterol-years score in FH/FDB heterozygotes.

Levels of total serum cholesterol in FH/FDB heterozygotes in different age groups before lipid-lowering therapy is started are plotted against age of the subjects (data from Table 1). Linear regression (y = 0.111x +7.408) has been used to generate the relationship between levels of total serum cholesterol and age from birth until the age of 60. Cholesterol-years scores for subjects who are put on lipid-lowering therapy at different decades and achieved a total serum cholesterol level of 5.4 mmol/l, are indicated.