Best Evidence Analyses and Commentary

ACC/AHA Lipid Guidelines 2013 - In a nutshell
By Tim Gordon and Bryan Koronowski, PharmD Candidates; Justin D. Scholl, PharmD, BCACP
May 2014

The American College of Cardiology (ACC) and the American Heart Association (AHA) recently developed a new guideline for the management of hyperlipidemia. The fundamental goal of this guideline is to identify a patient’s risk for atherosclerotic cardiovascular disease (ASCVD) and effectively manage those already diagnosed 1.  The authors define ASCVD as coronary heart disease, stroke, peripheral arterial disease, transient ischemic attack, and stable/unstable angina.1 Depending on the presence of a prior event or risk factors for the event, patients are targeted for either primary or secondary prevention with statin therapy.1  The strategy utilized within the new guideline departs from the previous guideline in that treatment  is no longer initiated or adjusted predominantly in response to lipid values, but rather, is based upon targeting patients to fixed dose of statin therapy corresponding to ASCVD or other risk factors. The rationale for this shift in recommendation is based on evidence from randomized controlled trials showing high-value endpoints, such as reductions in cardiovascular events or mortality, in which statin therapy was targeted to a fixed-dose of medication and not to a target LDL-C goal.1  

The four at-risk populations of individuals that will benefit from statin therapy based on the new guideline include:

1. Adult patients with clinical ASCVD

2. Adult patients with primary elevations of LDL–C ≥190 mg/dL

3. Patients 40-75 years of age with diabetes and LDL–C 70 to 189 mg/dL without clinical ASCVD

4. Patients 40-75 years of age without clinical ASCVD or diabetes with LDL–C 70 to 189 mg/dL and have an estimated 10-year ASCVD risk of 7.5% or higher

Another unique feature of the new ACC/AHA guideline is the use of an alternative Pooled Cohort Risk Assessment Equation to identify ten-year cardiovascular risk for patients aged 40-79, and lifetime cardiovascular risk for all patients, based upon pooled data from current literature1.   This tool was developed using data from trials included within the guideline research and differs somewhat from the traditional Framingham Risk Assessment utilized previously.  The calculator quantifies risk based on age, sex, race, lipid values, blood pressure, diabetes and smoking status. An online calculator can be found through the AHA website.1

Lifestyle modification still remains the foundation of therapy for lowering ASCVD risk and includes adhering to a heart healthy diet, regular exercise habits, avoidance of tobacco products and maintenance of a healthy weight.1 According to the new guideline, lifestyle modifications should be used in combination with statins for the identified patients at risk.

Following lifestyle modifications, statins are the medication class of choice for reduction of cardiovascular events associated with ASCVD, because they provide the greatest mortality benefit, have the fewest safety issues, and possess the largest body of high quality evidence from randomized controlled trials (RCT) .1  For patients at the highest risk of cardiovascular events, that is the four populations listed above, the guideline recommends the use of high-intensity statin therapy, regardless of LDL-C measurement.  High intensity statins include atorvastatin 40-80mg and rosuvastatin 20-40mg (Figure 1).  Lower doses or alternative statins may be used in this patient population in those patients who do not tolerate higher doses.  The use of additional lipid lowering agents is not specifically recommended in this guideline.  In patients who do not fall into the high risk groups, the use of moderate intensity statins or lifestyle modifications alone may be warranted based on additional criteria outlined within the guideline itself.

 

This new guideline gives clinicians more freedom to practice clinical judgment when treating patients at risk for ASCVD events.  It gives clinicians evidence to treat the patient to the extent of which both the clinician and patient are comfortable, taking into account individualized factors. Dr. Neil Stone, the chair of the expert panel that crafted the new guidelines, presents a scenario that addresses the aforementioned conundrum: “In secondary prevention, what if your patient is on high-intensity statin therapy and gets an LDL level of 78 mg/dL and is adhering to excellent lifestyle?...If he has to get to an optional goal of under 70 mg/dL as some would advocate, it means adding on medicines for which there is no proven benefit.”4

Some critics have pointed out that the online risk calculator, which differs somewhat from the Framingham Risk Assessment used in ATP III, greatly overestimates patient’s chances of having a heart attack or stroke leading to overtreatment.  This may be further compounded by the reduction of the 10-year risk treatment threshold to 7.5%, rather than 10% in the previous ATP III guideline.   Moreover, others point out that additional non-RCT data within the literature, which was omitted from the guideline, may have affected the recommendations had it been included.  The National Lipid Association pulled their support just before the guideline was released, disagreeing with the abandonment of LDL targets once patients began taking statins.5

In summary, the 2013 ACC/AHA Lipid Guideline primarily focuses on statin treatment in four major at risk groups with the goal of preventing primary or secondary heart attack, stroke or death.  This guideline focuses on the use of standard fixed-dose statin therapy as the means to improve cardiovascular outcomes in patients with ASCVD as opposed to targeting specific LDL-C goals.  Expert opinion appears to be divided between supporters and critics.  Nevertheless, clinicians now have more support to treat the individual patient, rather than the laboratory values, in such a fashion that utilizes both evidenced based medicine and clinical experience.

 

 References

1.   Stone NJ, Robinson J, Lichtenstein AH, et al. 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2013;():. doi:10.1016/j.jacc.2013.11.002.

2.   Jellinger, P., Smith, D., & Mehta, A., et al. (2012). American association of clinical endocrinologists’ guidelines for management of dyslipidemia and prevention of atherosclerosis. Endocrine Practice, 18(1), 1-78. Retrieved from https://www.aace.com/files/lipid-guidelines.pdf

3.   National Institutes OF HEALTH NATIONAL HEART, LUNG, AND BLOOD INSTITUTE. (2004, May). Atp iii guidelines at-a-glance quick desk reference. Retrieved from http://www.nhlbi.nih.gov/guidelines/cholesterol/atglance.pdf

4.   O’Riordan, Michael. New Cholesterol Guidelines Abandon LDL Targets. Medscape Cardiology. November 14, 2013.

5.   Kolata, Gina. Bumps in the Road to New Cholesterol Guidelines. The New York Times. November 25, 2013.

 


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