Table 3. Recommendation of drugs for lipid-lowering therapy.

Drugs	Recommendation	2019 European	2018 American	2018 Korean
Statins	Up to maximal tolerable dose to reach LDL-C target	I	I	I
Ezetimibe	Combine with a statin when the LDL-C target is not reached	I	IIa	IIa
	In the case of statin intolerance	IIa		IIa
PCSK9 inhibitors	In secondary prevention with very high-risk*	I	IIa	IIb
	When high LDL-C persists despite maximal tolerable dose statin/ezetimibe
	In primary prevention with FH & very high-risk*	I	IIb
	When high LDL-C persists despite maximal tolerable dose statin/ezetimibe
	In the case of statin intolerance	IIb
Bile acid-binding resin	Combine with a statin when the LDL-C target is not reached		IIb	IIb
	In the case of statin intolerance		IIb	IIa

Class I recommendation means “is recommended or is indicated” and defined when evidence and/or general agreement that a given treatment is beneficial. Class II recommendation is defined when conflicting evidence and/or divergence of opinion about the efficacy of the given treatment. Class IIa means “should be considered” and is defined when weight of evidence/opinion is in favor of efficacy. Class IIb means “may be considered” and defined when efficacy is less well established by evidence.

ASCVD, atherosclerotic cardiovascular disease; DM, diabetes mellitus; eGFR, estimated glomerular filtration rate; FH, familial hypercholesterolemia; HeFH, heterozygous familial hypercholesterolemia; CKD, chronic kidney disease; LDL-C, low-density lipoprotein-cholesterol.

^*In European guidelines, very high-risk group is defined as documented ASCVD, DM with target organ damage or ≥3 major risk factor, type1 DM of long duration, severe chronic kidney disease (eGFR <30 mL/min/1.73 m²), calculated SCORE ≥10%, or FH with ASCVD or major risk factors. In American guidelines, very high-risk of future ASCVD events is defined as multiple major ASCVD events or 1 major event and multiple high-risk conditions as follows. Major ASCVD events include recent acute coronary syndrome, history of myocardial infarction or ischemic stroke, and symptomatic peripheral artery disease. High risk conditions include age 65 years, HeFH, history of coronary revascularization, DM, hypertension, CKD (eGFR 15–59 mL/min/1.73 m²), current smoking, persistently elevated LDL-C ≥100 mg/dL despite maximal tolerable dose statin and ezetimibe, and history of congestive heart failure. In Korean guidelines, very high-risk group is defined as coronary artery disease, atherosclerotic ischemic stroke and transient ischemic attack, and peripheral artery disease.