Implantation of a biochemical and genetic screening programme for family hypercholesterolaemia. Collaboration between the clinical laboratory and lipid units: Design of the ARIAN Project

Implementation of a biochemical, clinical, and genetic screening programme for familial hypercholesterolemia in 26 centres in Spain: The ARIAN study

Background: Familial hypercholesterolemia (FH) is clearly underdiagnosed and undertreated. The aim of this present study is to assess the benefits of FH screening through a joint national program implemented between clinical laboratories and lipid units.

Methods: All clinical laboratory tests from 1 January 2017 to 31 December 2018 were reviewed, and those with LDL cholesterol (LDL-C) levels >250 mg/dl were identified in subjects >18 years of age of both sexes. Once secondary causes had been ruled out, the treating physician was contacted and advised to refer the patient to an LU to perform the Dutch Lipid Clinic Network score and to request genetic testing if the score was ≥6 points. Next Generation Sequencing was used to analyse the promoter and coding DNA sequences of four genes associated with FH (LDLR, APOB, PCSK9, APOE) and two genes that have a clinical overlap with FH characteristics (LDLRAP1 and LIPA). A polygenic risk score based on 12 variants was also obtained.

Results: Of the 3,827,513 patients analyzed in 26 centers, 6,765 had LDL-C levels >250 mg/dl. Having ruled out secondary causes and known cases of FH, 3,015 subjects were included, although only 1,205 treating physicians could be contacted. 635 patients were referred to an LU and genetic testing was requested for 153 of them. This resulted in a finding of sixty-seven pathogenic variants for FH, 66 in the LDLR gene and one in APOB. The polygenic risk score was found higher in those who had no pathogenic variant compared to those with a pathogenic variant.

Conclusion: Despite its limitations, systematic collaboration between clinical laboratories and lipid units allows for the identification of large numbers of patients with a phenotypic or genetic diagnosis of FH, which will reduce their vascular risk. This activity should be part of the clinical routine.

Prevalence of familial hypercholesterolemia phenotype and ten-year risk of cardiovascular events in a working population in primary prevention: The ICARIA study

BACKGROUND AND AIMS

We aimed to assess the prevalence of familial hypercholesterolaemia (FH) and to determine the incidence of cardiovascular events during a 10-year follow up in individuals with FH, compared to unaffected individuals in a working, middle-aged/young population.

METHODS AND RESULTS

576,724 active workers (36 ± 10 years-old, 70% men) without cardiovascular disease were given regular health check-ups and followed for a median of 8.5 years (i.e., 4,123,927 person-years). The FH phenotype was defined according to validated low-density lipoprotein-cholesterol thresholds, adjusted for age and sex. The primary outcome was a first cardiovascular event, whether fatal or non-fatal. We found that 707 workers (0.12% or 1 in 816 individuals) met the criteria for a heterozygous FH phenotype. During the follow-up, cardiovascular events occurred in 23 of 707 (3.25%) subjects with the FH phenotype and in 3297 of 576,017 (0.57%) subjects without the FH phenotype (p<0.001). The hazard ratio (HR, assessed with a Cox regression model) for the primary outcome was 5.7 (99% CI 3.33-9.78), before adjustments, and 4.7 (99% CI 2.62-8.58) after adjusting for sex, age, smoking, blood pressure, and diabetes. The HRs were significant for both men and women, but the magnitude of the effect was greater for men than for women.

CONCLUSIONS

Our findings confirmed the high incidence of cardiovascular disease in individuals with untreated FH. We showed that regular health check-ups in an active, and mostly young, working population could contribute to the early identification of FH. Therefore, this approach may provide an opportunity for early treatment.