An Evidence-Based Guide to Cholesterol-Lowering Guidelines

Since 2014, guidelines for the management of lipid disorders to reduce cardiovascular (CV) events have been updated in the United States, the United Kingdom, Europe, and Canada. Some of these guidelines are almost entirely evidence-based whereas others are a mix of evidence and expert opinion. Guidelines differ on such simple questions as to whether blood samples should be fasting or nonfasting, and whether low-density lipoprotein cholesterol (LDL-C) or another lipid parameter should be the primary focus of treatment. Different risk assessment tools are recommended by different guidelines. Lifetime risk is highlighted in some guidelines, with the suggestion that earlier treatment will reduce lifetime risk in younger people even when short-term risk is low. Some guidelines have numerical treatment targets that differ according to level of risk, while others eschew targets but recommend statins at high or moderate intensity to reduce LDL-C by ≥ 50% or 30%-50%, respectively. Statins are the backbone of therapy in all guidelines. Ezetimibe produced a 6.4% relative risk reduction in the only large clinical outcomes trial in which it was tested, and is recommended for high-risk patients with an inadequate response to statins, despite the high number needed to treat to prevent 1 CV event. Proprotein convertase subtilisin/kexin 9 inhibitors lack outcome data to support their use, but are approved for patients with familial hypercholesterolemia or clinical atherosclerotic CV disease who require additional LDL-C lowering beyond statins. All these new guidelines are aimed at improving the problem of undertreatment of high-risk groups, leading to better outcomes for these patients.