Low-Density Lipoprotein Cholesterol (LDL-C): How Low?

Low-density lipoprotein cholesterol (LDL-C) is a well-established major cardiovascular (CV) risk factor supported by clinical evidence showing decreased atherosclerotic disease events when LDL-C is therapeutically lowered. A reasonable approach is to tailor each patient's LDL-C target level depending on the initial LDL-C level and the perceived risk. Multiple clinical entities such as the newborn, hypobetalipoproteinemia, proprotein convertase subtilisin/kexin type 9 (PCSK9) missense mutations, and an unexpected excess response to a statin or other medications, are associated with very low LDL-C levels in otherwise healthy individuals. Therefore, an issue of major interest to clinicians who buy into "lower is better" for LDL-C in the high-risk CV patient is how low can and should the LDL-C be taken? Available information is discussed and placed into context. A definite safe lowest LDL-C level cannot be specified but there appears to be support that a level as low as 20 mg/dL (0.52 mmol/l) can be justified in the highest CV risk patients with extensive atherosclerosis where plaque stabilization and regression are necessary.