Detection of hidden cases of familial hypercholesterolemia in the Netherlands: a central laboratory data-driven strategy

Abstract Introduction Familial hypercholesterolemia (FH) is a common genetic disorder in which patients are at high risk for premature coronary artery disease (CAD) due to lifelong exposure to low-density lipoprotein cholesterol (LDL-C). Although early diagnosis and lipid lowering therapy (LLT) are essential to prevent adverse cardiovascular outcomes, FH patients remain globally underdiagnosed and undertreated, warranting novel screening methods to identify these patients. In the present study we aimed to evaluate whether existing central laboratory data can be utilized as a new method to detect undiagnosed FH patients. Additionally, we investigated the extent of underdiagnosis and undertreatment among patients with severe hypercholesterolemia in the Netherlands. Methods In this single-center, cross-sectional study, we selected individuals with at least one previously measured LDL-C plasma level ≥99.5th percentile for age and sex, from a central laboratory database containing lipid profiles of approximately 600.000 primary care patients. First, a blood sample was obtained to get more recent lipid values. Participating patients were subsequently asked to fill out a detailed questionnaire on medical and family history. Using these data, we calculated the Dutch Lipid Clinic Network (DLCN) criteria for each patient for the clinical diagnosis of FH. Results We identified a total of 5,100 patients with severe hypercholesterolemia (at least one LDL-C ≥99.5th percentile for age and sex) from the central laboratory database. Out of these, 1,206 patients (24%) participated in this study. Mean ± SD LDL-C corrected for LLT was 5.72 ± 1.83 mmol/L, 785 patients (65.1%) used LLT, and 150 patients (12.4%) had CVD in their medical history. In total, 131 patients (11%) had a persistent LDL-C ≥99.5th percentile for age and sex. DLCN criteria for phenotypic FH (DLCN score ≥6) were met by 302 patients (25%) of whom 39 patients (12.9%) had undergone prior genetic testing according to clinical guidelines. Of the 302 clinically diagnosed FH patients only 1 (0.3%) met the European Society of Cardiology (ESC) guideline recommending LDL-C targets