Updated Cholesterol Guidelines Accurately Identify Cardiovascular Event Risk

Compared with earlier recommendations for managing hyperlipidemia, the 2013 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for determining statin eligibility more accurately identify increased risk of cardiovascular events.

Results of a nearly decade-long follow-up study demonstrate the superiority of these updated lipid guidelines, which rely on a cardiovascular risk estimation equation to determine a particular patient’s 10-year risk of experiencing a cardiovascular event.

Critics of these guidelines have argued that this risk calculator could overestimate the probability of such an event, which might lead to overtreatment with statins.

The 2013 guidelines consider patients aged between 40 and 75 years as candidates for statin therapy if they fall into any of 4 categories.

The first 3 categories include populations at high cardiovascular risk that might have received statin therapy under previous guidelines, such as those with diabetes, atherosclerotic cardiovascular disease, or low-density lipoprotein (LDL) cholesterol levels ≥190 mg/dL. Controversially, the guidelines also consider those with a ≥7.5% 10-year cardiovascular event risk as patients who should contemplate taking lipid-lowering therapy.

Until now, this 7.5% threshold for qualifying otherwise healthy patients for therapy has been regarded as arbitrary, and many critics consider this criterion for statin eligibility too lenient.

However, new research has now proven the value of this updated treatment approach.

This study involved 2435 patients who were not taking lipid-lowering therapy and included the offspring and third-generation cohorts of the Framingham Heart Study. These patients first underwent cardiovascular risk assessment between 2002 and 2005 using a coronary artery calcification score and a comprehensive physical assessment.

For a median follow-up of 9 years, researchers assessed how many patients experienced cardiovascular events, primarily nonfatal strokes and heart attacks.

They found 2.4% of participants who were not eligible for statin therapy under the 2004 National Cholesterol Education Program’s Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III) guidelines developed incident cardiovascular disease (CVD). If the current ACC/AHA guidelines had been used 9 years ago to identify statin-eligible patients, only 1% of noneligible participants would develop CVD.

In the context of this study, this improvement in cardiovascular outcomes comes at the cost of nearly tripling the percentage of patients taking statins.

If the 2013 ACC/AHA guidelines had been in use 9 years earlier, more than one-third (39%) of the study participants would have been candidates for statin therapy. In contrast, the ATP III guidelines in place at the time qualified only 14% of them for such treatment.

Despite this dramatic increase in the proportion of statin-eligible patients, the results showed that the 2013 guidelines better select patients for statins than the 2004 guidelines. In fact, the authors estimated that 41,000 to 63,000 new CVD events could be prevented over the next 10 years if the 2013 guidelines are fully adopted, given that the 2004 guidelines are still used by many clinicians.

“This finding is…particularly important in participants at intermediate CVD risk on the Framingham Risk Scores—the most challenging group in clinical practice for whom to decide to initiate statin therapy,” the authors wrote.

At least in patient populations similar to those treated in the Framingham study, the 2013 ACC/AHA lipid guidelines are more effective than the 2004 guidelines in identifying patients who are appropriate candidates for statin therapy, this research suggests. While full implementation of these updated guidelines would translate to more than 8 million additional patients becoming eligible for statin therapy, it would also prevent tens of thousands of cardiovascular events over the coming decade.