The intention of this study was to profile the cohort from the Greek Registry for the prevalence of Familial Hypercholesterolemia (GRegistry-FH) by estimating the prevalence of coronary artery disease (CAD), myocardial infarction (MI), stroke, dyslipidemia, arterial hypertension, diabetes mellitus (DM), pre-DM, smoking, abnormal thyroid function (ATF), and lipid values. The GRegistry-FH is a prospective study involving door-to-door interviews conducted by trained interviewers. Overall, 7704 individuals aged ≥18 years, randomly selected from all the regions of Greece, participated. The prevalence of atherosclerotic cardiovascular disease (ASCVD) was 13.9% (CAD 6%, MI 3.2%, stroke 4.7%). Treated hypercholesterolemia was present in 20.1%, arterial hypertension in 24%, and DM in 11.3% individuals (25.5% had pre-DM). The prevalence of smoking was 37.9% (29% current) and the prevalence of ATF was 13.1% (hypothyroidism 11.3%). A family history of ASCVD was reported by 60.5% (CAD 32.2%, stroke 28.3%). The mean (SD) lipid values in mg/dL were as follows: total cholesterol of 201.8 (41.5), low-density lipoprotein cholesterol of 126.3 (30.1), high-density lipoprotein cholesterol of 51.9 (12.5), and triglycerides of 135.9 (64.7). The GRegistry-FH highlights the significant prevalence of ASCVD and its risk factors among Greek adults, indicating a pressing need for early detection and management strategies to mitigate ASCVD burden. This nationwide registry serves as a crucial tool for guiding public health policies and personalized preventive measures (NCT03140605).

Background and Aim: Familial hypercholesterolemia (FH) is a genetic disorder leading to severely elevated LDL-C and premature atherosclerotic cardiovascular disease (ASCVD). This study, the GRegistry-FH, provides the first population-based estimation of heterozygous FH (HeFH) prevalence and the clinical profile of affected individuals in Greece. Methods: A cross-sectional, questionnaire-based study was conducted on a representative sample of 7704 adults across 22 Greek regions. HeFH was assessed using the Simon Broome and Dutch Lipid Clinic Network (DLCN) criteria. Clinical characteristics and lipid-lowering therapy (LLT) attainment were compared between individuals with the HeFH phenotype and the general population. Results: The prevalence of HeFH was estimated at 1 in 188 individuals (Simon Broome) and 1 in 183 (DLCN). Individuals with the HeFH phenotype were significantly older and exhibited a much higher prevalence of hypertension (48.8% vs. 23.9%). Notably, individuals with the HeFH phenotype experienced myocardial infarction an average of 14 years earlier than non-FH individuals. Although 80.5% of individuals with the HeFH phenotype were on LLT, only 18.2% achieved LDL-C goals. None of the individuals with the HeFH phenotype with established ASCVD reached the target LDL-C of <1.4 mmol/L (55 mg/dL). Conclusions: HeFH is highly prevalent in Greece but remains largely underdiagnosed in younger ages and suboptimally treated. Despite high treatment rates, the vast majority of individuals with the HeFH phenotype fail to reach protective LDL-C targets. These findings emphasize the need for earlier identification and more aggressive combination lipid-lowering strategies.