Prevalence and Clinical Characteristics of Familial Hypercholesterolemia in Patients with Acute Coronary Syndrome according to the Current Japanese Guidelines: Insight from the EXPLORE-J study.

Aims: Little data exists for evaluating the prevalence and patient characteristics of familial hypercholesterolemia (FH) according to the latest 2022 guidelines for FH published by the Japan Atherosclerosis Society (JAS), which revised the Achilles tendon thickness (ATT) threshold from 9.0 mm in both sexes to 8.0 mm in men and 7.5 mm in women. This study used a nationwide registry of patients with acute coronary syndrome (ACS) to evaluate the prevalence of FH according to the latest diagnostic criteria for FH and to investigate the application of Achilles tendon imaging in the diagnosis of FH.A previous prospective observational study at 59 Japanese centers involving consecutive patients with ACS who were managed between April 2015 and August 8, 2016 was conducted to explore lipid management and persistent risk in patients hospitalized for ACS (EXPLORE-J). The study population consisted of 1,944 EXPLORE-J enrollees.

Results: According to the diagnostic criteria for FH in the 2022 JAS guidelines, the prevalence of probable or definite was among patients with ACS was 6.6% (127/1944). Among patients with premature ACS (male, age ＜55 years; female, age ＜65 years), the prevalence of FH was 10.1% (43/427). The mean ages were of the probable FH and definite FH groups were 59.9 and 61.0 years, respectively, while the mean age of the possible-or-unlikely FH group was 66.4 years (significantly older). Relative to the possible-or-unlikely FH group, the low-density lipoprotein cholesterol (LDL-C) levels were similar in the probable FH group and and significantly higher in the definite FH group.

Conclusions: The prevalence of FH was considerably higher than previously reported, especially for patients with premature ACS. The age and LDL-C levels of the patients in the probable FH and definite FH groups were similar.