1. New clinical guidelines from the American College of Cardiology (ACC) and the American Heart Association (AHA) recommend statin use in certain patient populations based on age, 10-year atherosclerotic cardiovascular disease (ASCVD) risk level, and blood LDL-C level.
2. The guidelines also suggest use of a new equation for estimating ASCVD risk in patients.
Evidence Rating Level: 1 (Excellent)
Study Rundown: ASCVD is the leading cause of death in Americans, and its treatment costs the US healthcare system billions of dollars annually. The ACC/AHA released updated clinical guidelines for the screening and management of ASCVD. These guidelines emphasize an active, healthy lifestyle and diet as the primary methods for preventing ASCVD in all patients. In addition, the guidelines also advocate the use of statins as primary prevention in patients with: (1) clinical ASCVD, (2) LDL levels of 190 mg/dL or higher, (3) aged 40 to 75 years with diabetes and LDL levels of 70 to 189 mg/d and, (4) those aged 40 to 75 years without diabetes and with a ten-year ASCVD risk of 7.5% or higher.
Importantly, the new guidelines do not show enough evidence to support treatment to LDL or non-HDL cholesterol goals in patients. Rather, at-risk patients should be maintained on proper statin therapy for as long as they can tolerate the drug without serious side effects (e.g. myopathy). The last major recommendation states that the Pooled Cohort Equations are the best option for estimating ten-year ASCVD risk as a precursor to statin initiation.
These new guidelines have sparked some controversy. In particular, the abandonment of the LDL and non-HDL targets for statin treatments has been criticized. While using these cholesterol levels as the sole determinant of statin therapy initiation/maintenance is widely regarded as ill-advised, these lipid measurements can still serve as valuable metrics of treatment efficacy during follow-up visits. Also, the new risk calculation method has not been released free of concerns, since it has been reported to overestimate the risk for ASCVD by 70% to 150%. The many factors comprising the algorithms behind the risk equations should be reviewed in conjunction with randomized, controlled trials and adjusted as necessary to refine the equations’ predictive value.
In-Depth [systematic review]: The National Heart, Lung and Blood Institute (NHLBI) convened the Adult Treatment Panel IV (ATP-IV) in 2008 in order to update cholesterol guidelines set forth in 2001 by the ATP-III. This was done by reviewing multiple randomized, controlled trials (RCTs) and meta-analyses of RCTs that studied cardiovascular outcomes. The reviews sought to answer questions about the evidence behind LDL and non-HDL levels as targets of treatment and about ASCVD event reduction versus adverse event occurrence for each cholesterol-lowering drug class. The strength of the evidence presented in each article reviewed was rated and resulting recommendations were graded according to criteria established by both the NHLBI and the ACC/AHA. The risk assessment equations used in the new risk calculator were conceived using data from five representative cohorts of African American and non-Hispanic white men and women. In September 2013, the ATP-IV’s recommendations were passed along to the ACC/AHA, where they were reviewed again before approval was given by both of these agencies.
By Nick Woolf and Aimee Li, MD
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