The several classes of lipid lowering drugs may differ in both their impact on the cholesterol profile and adverse effects. For example, some may lower low density lipoprotein (LDL) levels more so than others, while others may preferentially increase high density lipoprotein (HDL). Clinically, the choice of an agent depends on the patient's cholesterol profile, cardiovascular risk, and the liver and kidney functions of the patient, evaluated against the balancing of risks and benefits of the medications. In the United States, this is guided by the evidence-based guideline most recently updated in 2018 by the American College of Cardiology & American Heart Association.