Guidelines Miss Younger MI Patients for Cholesterol Treatment

A substantial proportion of younger patients who had myocardial infarction (MI) did not meet recommendations for primary prevention statin therapy under 2013 or 2018 guidelines, or for high-intensity cholesterol treatment for secondary prevention under 2018 guidelines, a retrospective study showed.

Only 56.7% of adults under age 55 who had MI met a Class I or Class IIa recommendations for treatment under 2013 guidelines from American College of Cardiology/American Heart Association (ACC/AHA), reported Ann Marie Navar, MD, PhD, of Duke University, and coauthors in Journal of the American College of Cardiology.

Just 46.4% of younger adults qualified for statin therapy under 2018 AHA/ACC guidelines, they added. Younger patients less frequently met very high-risk criteria for intensive secondary prevention lipid-lowering therapy than older adults (28.3%, compared with 40.0% for people 55 to 65 years old, and 81.4% for people 66 to 75; P < 0.01).

“Most younger patients with premature MI are not identified as statin candidates before their event on the basis of the 2018 guidelines, and most patients with premature MI are not recommended for intensive post-MI lipid management,” Navar and colleagues wrote.

“Because current diagnostic and therapeutic approaches may not adequately identify at-risk young adults, it is useful to consider a few alternative approaches,” noted Ron Blankstein, MD, of Harvard University, and Avinainder Singh, MD, MMSCb, of Yale University, in an accompanying editorial.

“The atherosclerotic cardiovascular disease (ASCVD) risk score calculator underestimates risk in some young adults, and statin therapy should be more strongly considered among young adults with borderline risk (5% to 7.5%), especially when either traditional or nontraditional risk factors are present,” they wrote.

“It is important to recognize that certain risk factors may be particularly important among young individuals, including tobacco use, low high-density lipoprotein cholesterol, obesity, and substance abuse,” the editorialists pointed out. “When considering these factors, it is apparent that there are many more opportunities to reduce the risk of MI beyond just cholesterol-lowering agents.”

An earlier study of the 2013 AHA/ACC guideline in 1,475 MI patients age 50 or younger found that only 29% would have met criteria for statin eligibility, highlighting concerns that younger patients might not have accurate risk assessment in part due to age-dependent ASCVD risk measures.

The 2018 guidelines changed statin eligibility for primary prevention and added new intensive lipid-lowering therapies for secondary prevention (nonstatin lipid lowering therapies including proprotein convertase subtilisin/kexin type 9, [PCSK9] inhibitors). Also, a prior class IIa statin recommendation for those with estimated ASCVD risk between 5% and 7.5% was changed for to class IIb, also requiring a “risk enhancer,” including connective tissue disease, premature menopause (before 40 years of age), family history of coronary artery disease, ethnicity, HIV/AIDS, estimated glomerular filtration rate <60 ml/min, or metabolic syndrome.

To determine how guideline changes affected identification for preventive therapy in young adults with MI, Navar and colleagues determined guideline-based class I and IIa eligibility for statin therapy in primary prevention, along with eligibility for intensive lipid-lowering therapy, in 6,639 adults from the Duke Databank for Cardiovascular Disease. Patients had an index first MI between 1995 and 2012. A composite endpoint including all cause death, recurrent MI, or stroke was used to compare those at very high versus lesser degrees of risk and other groups during median 8-year follow-up.

In the total sample, 41% were under age 55 (younger), 35% were 55 to 65 (middle age), and 24% were 66 to 75 (older).

“The previous Class IIa recommendation for statins in individuals with a 5% to 7.5% 10-year ASCVD score in the 2013 ACC/AHA guideline was down-graded to a Class IIb recommendation in the 2018 guideline” and was not included in the analysis, the authors noted.

Compared with the 2013 guidelines, 2018 guidelines identified fewer younger adults eligible for statin therapy at the time of index MI (46.4% versus 56.7%; P< 0.01).

As in older age groups, very high-risk criteria were associated with increased risk of major adverse cardiovascular events in those <55 years of age (HR 2.09, 95% CI 1.82-2.41; P < 0.001).

Compared with the middle-age and older groups, younger adults more frequently:

• Were smokers (52% versus 38% versus 22%, respectively).
• Were obese (42% versus 34% versus 31%, respectively).
• Had metabolic syndrome (21% versus 19% versus 17%, respectively).
• Had higher low-density lipoprotein cholesterol (117 versus 107 versus 103 mg/dl, respectively).

In the younger group, 6.2% met class IIb statin criteria, including a 10-year ASCVD risk score between 5% and 7.5% and one risk enhancer.

“Ultimately, greater primordial and primary prevention efforts are needed,” the editorialists wrote. “If our goal is to achieve the greatest possible reduction in cardiovascular events, we should not miss any opportunities to improve prevention.”

Limitations include use of earliest available data for lipids which was after the index MI in some cases, when treatment may have changed levels.

1. A substantial proportion of younger patients who had myocardial infarction (MI) did not meet recommendations for primary prevention statin therapy under 2013 or 2018 guidelines, or for high-intensity cholesterol treatment for secondary prevention under 2018 guidelines, a retrospective study showed.

2. In some younger MI patients, the atherosclerotic cardiovascular disease (ASCVD) risk score calculator underestimates risk and statin therapy should be more strongly considered in those with borderline risk, the editorialists maintained.

Paul Smyth, MD, Contributing Writer, BreakingMED™

Cat ID: 358

Topic ID: 74,358,730,358,6,142,192,925