Familial hypercholesterolemia in a European Mediterranean population-Prevalence and clinical data from 2.5 million primary care patients

Background: Familial hypercholesterolemia (FH), the most frequent hereditary cause of premature coronary heart disease (CHD), is underdiagnosed and insufficiently treated.

Objectives: The objectives of the study were to estimate the prevalence of the FH phenotype (FH-P) and to describe its clinical characteristics in a Mediterranean population.

Methods: Data were obtained from the Catalan primary care system's clinical records database (Catalan acronym: SIDIAP). Patients aged >7 years with at least 1 low-density lipoprotein cholesterol measurement recorded between 2006 and 2014 (n = 2,554,644) were included. Heterozygous FH-P and homozygous FH-P were defined by untreated low-density lipoprotein cholesterol plasma concentrations. The presence of cardiovascular diseases and risk factors was defined by coded medical records from primary care and hospital discharge databases.

Results: The age- and sex-standardized prevalence of heterozygous FH-P and homozygous FH-P were 1/192 individuals and 1/425,774 individuals, respectively. In the group aged 8 to 18 years, 0.46% (95% confidence interval: 0.41-0.52) had FH-P; overall prevalence was 0.58% (95% confidence interval: 0.58-0.60). Among patients with FH-P aged >18 years, cardiovascular disease prevalence was 3.5 times higher than in general population, and CHD prevalence in those aged 35 to 59 years was 4.5 times higher than in those without FH-P. Lipid-lowering therapy was lacking in 13.5% of patients with FH-P, and only 31.6% of men and 22.7 of women were receiving high or very high-intensity lipid-lowering therapy.

Conclusion: Prevalence of FH-P was higher than expected, but underdiagnosed and suboptimally treated, especially in women. Moreover, treatment started late considering the high CHD incidence associated with this condition.