Clinical guidelines for cholesterol management may have two blind spots when it comes to heart attack prevention: Most younger adults with premature coronary artery disease who’ve had a myocardial infarction don’t meet guideline criteria for preventative statin therapy, and survivors under age 55 don’t meet the criteria for continuing nonstatin lipid-lowering treatments, a large single-center retrospective study has shown.
“The classic approach we’ve taken to identifying young adults for prevention is inadequate in younger adults,” corresponding author Ann Marie Navar, MD, PhD, of Duke University, Durham, N.C., said in an interview. “While awaiting more definitive research we should at minimum be using all the tools at our disposal, including broader use of coronary artery calcium [CAC] scoring, to identify young people who may benefit from statin therapy.”
The retrospective observational study analyzed records of 6,639 adults who had cardiac catheterization at Duke University Medical Center from 1995 to 2012 for a first myocardial infarction with obstructive coronary artery disease. The study considered those under age 55 years as “younger” patients, comprising 41% of the study group (2,733); 35% were “middle-aged” at 55-65 years (2,324) and 24% were “older,” at 66-75 years (1,582).
The report, published online Aug. 3 in the Journal of the American College of Cardiology, noted that most of the adults with premature CAD did not meet criteria for preventative statin therapy before their first MI based on ACC/American Heart Association clinical guidelines from 2013 and 2018. It also noted that younger MI survivors are also less frequently eligible for secondary prevention with intensive nonstatin lipid-lowering therapies than are older adults despite a much longer potential life span – and opportunity for another MI – for the former.
The researchers sought to evaluate the real-world implications of changes made in the 2018 guideline for adults who develop premature ischemic heart disease, and found that fewer younger patients qualify for preventative statin therapy under the 2018 guidelines.
“Younger individuals with very high-risk criteria are at higher risk of major adverse cardiovascular events, a finding supporting the appropriate implementation of intensive lipid-lowering therapies in these patients,” wrote lead author Michel Zeitouni, MD, MSc, and colleagues.
The investigators reported that younger adults were significantly less likely to meet a class I recommendation for statins under the 2013 guideline (42.9%), compared with their middle-aged (70%) and older (82.5%) counterparts; and under the 2018 guideline, at 39.4%, 59.5%, and 77.4%, respectively (both P < .001).
Similarly, when both class I and class IIa recommendations were accounted for, younger patients were significantly less likely than were middle-aged and older patients to be eligible for statins before their index MI under both the 2013 (56.7%, 79.5%, and 85.2%, respectively and 2018 guidelines (46.4%, 73.5%, and 88.2%, respectively (both P < .01).
After their first MI, one in four younger patients (28.3%) met the very high-risk criteria compared with 40% of middle-aged and 81.4% of older patients (P trend < .001). In 8 years of follow-up, patients with very high-risk criteria based on the 2018 guideline had twice the rate of death, nonfatal MI, or stroke (hazard ratio [HR]: 2.15; 95% confidence interval, 1.98-2.33; P < .001).
The researchers acknowledged that the 2018 guideline took the important step of implementing risk enhancers – patient characteristics such as obesity and metabolic syndrome – along with the 10-year atherosclerotic cardiovascular disease (ASCVD) risk score to better identify high-risk young individuals who need statins. However, they also noted that the ability of the guidelines to identify young adults before their first MI “remains suboptimal.”