The rationale and design of the national familial hypercholesterolemia registries in Turkey: A-HIT1 and A-HIT2 studies

OBJECTIVE
Familial hypercholesterolemia (FH) is a genetic disease characterized by extremely high levels of cholesterol, leading to premature atherosclerosis. Although many countries have already addressed the burden of FH by means of national registries, Turkey has no national FH registry or national screening program to detect FH. Creation of a series of FH registries is planned as part of Turkish FH Initiative endorsed by the Turkish Society of Cardiology to meet this need. This article provides detailed information on the rationale and design of the first 2 FH registries (A-HIT1 and A-HIT2).

METHODS
A-HIT1 is a nationwide survey of adult homozygous FH (HoFH) patients undergoing low-density lipoprotein (LDL) apheresis (LA) in Turkey. A-HIT1 will provide insight into the clinical status of HoFH patients undergoing LA. Primary objective of this cross-sectional study is to identify how HoFH patients on LA are managed. Inclusion criteria are age >12 years, diagnosis of HoFH, and regular LA treatment. All available apheresis centers were electronically invited to participate in the study. The principal physicians of each center will respond to a questionnaire regarding their attitude toward LA. For each patient, another questionnaire will be used to collect data on clinical status, medication use, and disease data. In addition, patients will be asked to complete self-report questionnaires that provide information on quality of life, disease-related anxiety, and depression. A-HIT2 is a registry of adult FH patients presenting at outpatient clinics. At least 1000 FH patients will be recruited from 30 outpatient clinics representing the 12 statistical regions in Turkey based on the EU NUTS classification. Sites specializing in cardiology, internal medicine, and endocrinology were invited to participate. The primary objective of this cross-sectional study is to determine clinical status and management of patients in Turkey diagnosed with FH. Eligibility for screening was defined as having LDL-cholesterol level >160 mg/dL. Inclusion criteria are age >18 years and diagnosis as possible FH (total score of >2 according to Dutch Lipid Clinic Network criteria). In addition to measuring clinical status of patients, a short survey to assess patient level of disease awareness will also be administered.

CONCLUSION
A-HIT1 and A-HIT2 are the first nationwide FH registries in Turkey and will provide important information on the management of Turkish FH patients. In addition, it is planned that they will guide establishment of a national policy for the diagnosis and treatment of FH in Turkey.