New Cholesterol Guideline focuses on individual risk assessment and therapies to optimise patient care

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Mel Kowalski and Cia Connell

The 2018 AHA/ACC Guideline on the Management of Blood Cholesterol was released on 10th November at AHA 2018 conference in Chicago. 

More detailed risk assessments are among the biggest changes in the update, with the aim of individualising risk status by combining these investigations with clinician-patient risk discussion before starting statin therapy.

The guideline includes the evaluation of risk-enhancing factors whose presence help to confirm a higher risk state. Identification of these factors can help further inform decision making to initiate or intensify statin therapy. A risk discussion considering these enhancers may be useful for some patients to identify factors influencing individual risk beyond that of the 10-year ASCVD risk prediction tool applied to the general population.

Risk enhancers include:

  • co-morbid conditions such as chronic kidney disease, metabolic syndrome, inflammatory diseases (especially rheumatoid arthritis, psoriasis, HIV) and conditions specific to women (e.g. pre-eclampsia and premature menopause)
  • Ethnicity (e.g. South Asian ancestry)
  • Lipid/biomarkers such as persistently elevated triglycerides, hs-CRP, Lp(a), apoB and Ankle-Brachial Index

The American guidelines also emphasize that high cholesterol at any age can increase lifetime risk for heart disease and stroke. A heart healthy lifestyle starting in younger individuals can reduce the development of ASCVD risk factors.

New recommendations for the role of coronary artery calcium scoring (CAC) are also included.  Testing can be considered in adults where a decision about statin therapy is uncertain and additional information is needed to clarify ASCVD risk. A CAC of zero lowers risk and statin therapy may be avoided or delayed on the provision that high-risk behaviours or characteristics are not present such as smoking, diabetes or family history. A positive CAC will further inform the decision to initiate statin therapy.

What’s different for treatment thresholds and drug treatments?

The Australian Guidelines for the management of Absolute cardiovascular disease risk (2012) define a group of patients entitled ‘clinically determined high risk’ – those in whom lipid lowering therapy is recommended without a need to calculate absolute risk. The 2018 American guidelines have effectively broadened this category, and thus treatment with statins, by the inclusion of the following criteria:

  • Severe primary hypercholesterolemia (defined as serum cholesterol ≥ 4.9mmol/L) - in Australia, this group is defined as serum cholesterol >7.5 mmol/L
  • Patients 40 to 75 years of age with diabetes mellitus - in Australia, this group is limited to diabetes and age >60 years

Ezetimibe and PCSK9 inhibitor use are now supported by randomised controlled trial evidence. In the American guidelines, their use is limited mainly to secondary prevention in patients at very high risk of new ASCVD events. They are also recommended in severe primary hypercholesterolaemia where low density lipoprotein- cholesterol is still high despite statin therapy.

The new guideline has been simultaneously published in the Journal of the American College of Cardiology and Circulation.

The Heart Foundation recommends that the Guidelines for the Management of Absolute Cardiovascular Disease Risk 2012, developed by the National Vascular Disease Prevention Alliance (NVDPA), be updated. Federal funding should be provided to ensure that this takes place as soon as is practicable.

AHA = American Heart Association; ACC = American College of Cardiology; apoB = apolipoprotein B; ASCVD = atherosclerotic cardiovascular disease; HIV = human immunodeficiency virus; hsCRP, high-sensitivity C-reactive protein; Lp(a) = lipoprotein (a); PCSK9 = proprotein convertase subtilisin/kexin type 9