Current Status and Clinical Characteristics of Familial Hypercholesterolemia Patients in Korea: A Multicenter, Real-World Experience

<b>Background:</b> Familial hypercholesterolemia (FH) continues to be underrecognized and inadequately treated. We aimed to investigate the current status of FH diagnosis and treatment in South Korea. <b>Methods:</b> Patients from two tertiary hospitals in South Korea between 2010 and 2023 with either a diagnosis of FH (ICD-10 code: E7800), had <i>LDLR</i>, <i>APOB</i>, or <i>PCSK9</i> mutations, or had low-density lipoprotein cholesterol (LDL-C) levels exceeding 325 mg/dL were considered for inclusion. Demographic and laboratory characteristics as well as pharmacologic treatment patterns were assessed. <b>Results:</b> A total of 148 patients were retrospectively identified. The mean age at diagnosis was 49.3 years, and 33 (22.3%) had a history of established atherosclerotic cardiovascular disease (ASCVD). The majority of patients were diagnosed in the cardiology or endocrinology departments. The LDL-C level at enrollment was 247 ± 98 mg/dL (conversion to treatment-naïve LDL-C: 343 ± 141 mg/dL), which decreased to 122 ± 60 mg/dL after one year, achieving guideline-recommended target levels in 11.5%. A high proportion of patients were treated with statins (80.2%) and ezetimibe (64.9%), but the use of proprotein convertase subtilisin/kexin type 9 inhibitors was low (11.7%). Patients diagnosed after 2020 achieved significantly lower LDL-C levels at one year compared to those diagnosed between 2020 and 2019 (107 ± 50 vs. 152 ± 68 mg/dL, <i>p</i> = 0.003). Two ischemic strokes and two myocardial infarctions occurred during a median follow-up of 25.3 months. <b>Conclusions:</b> FH is frequently diagnosed late after the onset of clinical ASCVD and is undertreated, although recent trends show improvement. Our results again underline the need for proper screening and identification of patients with FH.