Approximately one-half of statin candidates have no coronary artery calcium (CAC), suggesting significant heterogeneity among those eligible for statins under the new American College of Cardiology (ACC) and American Heart Association (AHA) cholesterol management guidelines.
The ACC and AHA estimate that 45 million adults in the United States are recommended for statin therapy on the basis of their 10-year atherosclerotic cardiovascular disease (ASCVD) of ≥7.5%. CAC can measure coronary atherosclerosis; high levels are associated with a 10-fold risk of ASCVD events. The absence of CAC, however, suggests low risk for ASCVD events, which could allow patients to consider more flexible treatments.
“As the absolute ASCVD risk decreases, so does the net benefit of any intervention with a relative risk reduction that does not increase with lower patient risk,” the authors wrote. “In these circumstances, the absence of CAC can afford significant value in promoting shared decision-making and better informed patients, who may consider avoiding statins to focus on prudent lifestyle changes, of their choices.”
The analysis published in the Journal of the American College of Cardiology included 4758 participants ages 45 to 84 years without ASCVD from the Multi-Ethnic Study of Atherosclerosis (MESA). Researchers collected information about cardiovascular risk factors like total cholesterol, presence of diabetes, and hypertension from participants in 6 communities across the United States.
The 10-year ASCVD risk score for MESA was determined by age, total cholesterol, systolic blood pressure, treatment of hypertension, smoking status, and history of diabetes mellitus. To evaluate statin eligibility, participants were categorized as either statin recommended or statin considered, according to ACC and AHA guidelines. All participants had 2 computed tomography scans to determine the CAC scores.
The new ACC/AHA cholesterol management guidelines recommended 50% of the MESA participants for moderate to high intensity statins, and 77% were eligible because they had a 10-year ASCVD risk of ≥7.5%. Of the participants who were recommended statins, 41% had CAC=0. Among the patients considered for moderate-intensity statins, 57% had a CAC=0, and among the patients who were either recommended or considered for statins, 44% had CAC=0.
The results showed that 5.2% of the participants had ASCVD events over the 10 year follow-up period, and 3.3% had coronary heart disease events.
The authors noted that by avoiding the extremes of ASCVD (<5% and >20%), 49% of the study participants with a 10-year ASCVD risk prediction between 5% and 20% and CAC=0 can be reclassified below the risk threshold to be considered for statin therapy.
- Nasir K, Bittencourt M, Blaha M, et al. Implications of Coronary Artery Calcium Testing Among Statin Candidates According to American College of Cardiology/America Heart Association Cholesterol Management Guidelines. J Am Coll Cardiol. 2015;66(15):1657-1668. doi: http://dx.doi.org/10.10.16/j.jacc.2015.07.066.