Avinainder Singh (Brigham and Women’s Hospital, Harvard Medical School, Boston, USA) and others report in the Journal of the American College of Cardiology that most “young” (aged 50 years or younger) patients who have had a myocardial infarction would not—according to current guidelines—have been eligible for statin therapy prior to their event. However, 83% of them have at least one risk factor for cardiovascular disease.
Singh et al note that while the prevalence of myocardial infarction, according to recent reports, has decreased, there has been no reduction in young adults “and young women, in particular, continue, to have worse cardiovascular outcomes than men”. They add that predicting the risk of myocardial infarction is challenging in this subpopulation as “most risk calculators fail to identify susceptible young adults at high risk”.
However, the authors comment that current guidelines—the 2013 American College of Cardiology/American Heart Association (ACC/AHA) for cholesterol lowering and the 2016 United States Preventative Services Task Force (USPSTF) for primary prevention statin use—have significantly expanded the number of individuals who are candidates for statin therapy compared with previous editions. “Therefore we sought to determine how contemporary guidelines perform in identifying the need for statin therapy among a cohort of men and women who experienced a first-time myocardial infarction at a young age,” Singh et al write.
Using data from the YOUNG-MI registry (which includes patients who experienced a myocardial infarction at 50 years or younger), the authors identified 1,475 patients (median age 45 years) who had had a myocardial infarction and were not receiving statin therapy prior to the event. Of these, 17.3% were under the age of 40 at the time of the event.
They comment: “When examining the prevalence of risk factors, 1,225 (83%) patients had at least one of the following: diabetes, dyslipidaemia, hypertension or smoking,” adding that dyslipidaemia was the most common factor (55%). Furthermore, the median atherosclerotic cardiovascular disease (ASCVD) risk score was 4.8% and 72% of patients had a risk score of <7.5%. When lifetime cardiovascular risk was considered, 80.3% of patients were at high risk.
However, according to the 2013 ACC/AHA guidelines, only 31% of patients—prior to the myocardial infarction—would have met the criteria for statin therapy and only 18% would have met the criteria for the consideration of statin therapy. Thus, under this guideline, 51% of patients would not have been eligible for primary prevention statin therapy. With the USPSTF recommendations, these figures would have been, respectively, 18%, 11%, and 71%.
Singh et al report: “When applying both the 2013 ACC/AHA and the 2016 USPTF recommendations to our entire study population, only 742 (50%) patients would have been categorised as stain eligible—ie. categorised as statin recommended or statin considered by either guideline—prior to their myocardial infarction”. They add that “23% and 43% of patients with at least of the following risk factors—diabetes, hypertension, dyslipidaemia, and smoking—would not have been eligible for statin therapy, according to the 2013 ACC/AHA guideline and the 2016 USPSTF recommendations, respectively”.
The authors conclude: “The vast majority of adults who present with a myocardial infarction at a young age would not have met current guideline-based treatment threshold for statin therapy prior to their myocardial infarction. These findings highlight the need for developing better risk assessment tools among young adults.”
Senior author of the study Ron Blankstein (Brigham and Women’s Hospital, Harvard Medical School, Boston, USA) told Cardiovascular News: “Our results emphasise that we need to do a better job identifying and treating underlying risk factors for coronary artery disease. Importantly, individuals with underlying risk factors, or a family history of premature coronary heart disease, should not be overly reassured if they have a ‘low risk’ by current risk assessment approaches used in our guidelines. This is because these risk scores are heavily influenced by age, and thus may not perform well in younger individuals. Our results suggest that that there is a need to better identify at-risk younger individuals who warrant more aggressive lifestyle, and in some cases pharmacologic therapy.”
He added that while one such approach may be the use of coronary artery calcium scanning in selected individuals, in the future, other techniques such as genomic and proteomic analyses—when combined with other risk factors—may allow better identification and treatment of at-risk individuals.