The wait is over: The cholesterol treatment guidelines are here
After a long wait, the guideline previously known as ATP IV is here. We would like to be among the first to congratulate the expert panel on completing the new 2013 American College of Cardiology/American Heart Association Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults. There is no doubt that it was a large undertaking to translate a decade’s worth of rich and novel science that transformed the way we approach our patients at increased risk for atherosclerotic CVD (ASCVD). With these guidelines hot off the press, this article examines some of its key features.
Primary prevention is here to stay
The 2013 guidelines are an emphatic declaration that primary prevention with selective use of statin therapy is here to stay. After years of careful review of statin trials, the expert writing group determined that the role for statins in primary prevention should be expanded beyond CHD to include stroke prevention, whether fatal or nonfatal.
Rather than focusing solely on total mortality, the panel concluded that prevention of major nonfatal ASCVD events can reduce the large burden of disability from nonfatal stroke and nonfatal CHD events. Getting ahead of the curve may be critical to tackling the projected tripling of ASCVD-related health care costs in the next 20 years.
Risk assessment, treatment threshold and statin therapy
In essence, the new guideline broadens risk assessment, lowers the treatment threshold, and now explicitly identifies statins as the first-line treatment for high blood cholesterol and increased CV risk. The updated ASCVD risk calculator adds stroke to MI as an endpoint to look at ASCVD risk, rather than just CHD risk, in the next decade. In addition, separate NHLBI risk-prediction equations were developed for non-Hispanic white and black men and women.
Rather than the prior threshold of MI/CHD death risk of 20%, the panel strongly recommends statin therapy for patients surpassing a 7.5% threshold of ASCVD risk in the next decade.
Many will qualify for statin Rx
Based on NHANES data, it would seem that many more adults will qualify for statins because the 7.5% 10-year ASCVD risk threshold is exceeded by more than half of black men in their 50s and more than one-third of white men in that age range. Virtually all men will surpass this threshold by their late 60s. In contrast, for women in their 60s about 70% of black women and 30% of white women will have a 10-year ASCVD risk >7.5%.
Given the 7.5% ASCVD risk cutoff is featured so prominently in the guidelines, one would hope that quantification of risk by the new algorithm would be as accurate as possible. However, the precision of the risk calculator at the patient level appears disappointing based on C-statistics of only 0.6 to 0.75 in the MESA and REGARD trials.
Despite a wealth of research on additional tools like high-sensitivity C-reactive protein and coronary artery calcium in the last decade to improve risk assessment in selected patients, their use is limited in this guideline. These tools are not recommended in a person with normal lipid values but whose risk score exceeds the 7.5% threshold due to age and mild hypertension. Rather, the new guidelines take a one-size-fits-all approach, not considering that patients age differently, and suggesting one consider physiologic age.
New algorithm is simplified
Nevertheless, the new algorithm for initiating statin therapy is substantially simplified compared with prior ATP guidelines, which we view as a welcome change, and should help promote better implementation in clinical practice. In addition to the new recommendation to use statin therapy in primary prevention adults with >7.5% ASCVD risk, the panel recommends statin therapy in the following three scenarios:
Would the selective use of atherosclerosis imaging, however, help promote more judicious use of statins and better personalize patient care? We would respond in the affirmative.
Adequacy of therapy, follow-up management
In contrast to prior ATP guidelines, recent AHA/ACC guidelines and contemporary lipid guidelines around the world, these guidelines provide less-explicit guidance on assessing the adequacy of therapy and follow-up management. Informing such guidance requires a more balanced look at the totality of current best evidence, not just primary reports from trials reported before December of 2009. Lipid goals were previously a major focus of the guidelines. Now they are minimized, which will cause confusion, and unfortunately are not based on proof for the superiority of the new approach. In the future, we predict we will end up somewhere in between.
What is ‘evidence-based?’
The new guideline contrasts with ATP III in implying a more evidence-based approach. However, if the panel applied the same definition of “evidence” used for examining lipid goals to the new ASCVD risk calculator, then the answer is the same: “no evidence.” This speaks to the definition of “evidence” in this guideline.
The panel has a different definition of “evidence-based” than the traditional definition. David Sackett and the pioneers of “evidence-based medicine” wrote a helpful article that said, “Evidence-based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.” It was further specified that “evidence-based medicine is not restricted to randomised trials and meta-analyses. It involves tracking down the best external evidence with which to answer our clinical questions.”
This guideline, unfortunately, did not track down all of the best evidence.
In summary, well-intentioned CV specialists often disagree, but we wholeheartedly support at least 90% of the new guidelines, which declare that primary prevention is here to stay. While many more adults will now qualify for statin therapy, heart-healthy dietary and exercise habits remain the foundation of primary prevention efforts. Following these new guidelines will allow clinicians to markedly reduce CVD events in their patients.
Read more guideline commentary here
Note: The guidelines were simultaneously published in Circulation and the Journal of the American College of Cardiology.
Disclosure: Blumenthal, Martin and Ojeifo report no relevant financial disclosures.