Patients older than 18 years old and have a serum LDL-C≥250 mg/dL between January 2010 and December 2016. Patients with a serum TSH≥10 mIU/mL, patients with glomerulonephritis or nephrotic syndrome, patients with ALT or AST higher than 3 times of normal limits and patients with serum triglyceride >400 mg/dL were excluded.

Patients with a serum LDL-C≥250 mg/dL were identified from the database of our hospital. Dutch Lipid Clinical Network Criteria was used to classify patients as definite, probable and possible FH. Patients were reached by phone and a questionnaire was applied. The questionnaire consisted of questions related with clinical and physical examination findings defined in theDutch Lipid Clinical Network Criteria. Total cholesterol, LDL-C, HDL-C, triglyceride levels were obtained from the medical records. Patients were asked whether they were using lipid lowering drugs. If they were not using, the cause of this was asked. By this way, we determined the rate of use of lipid lowering drugs in patients with LDL-C≥250 mg/dL and have definite, probable or possible familial hypercholesterolemia