Disease-Guided Initiation of Statin Therapy in the Elderly

Study Questions:

Does coronary artery calcium (CAC) or carotid artery plaque burden (cPB) improve the identification of adults who benefit from statin therapy?

Methods:

Data from the BioImage Study, a prospective observational cohort, were used for the present analysis. Participants were men ages 55-80 years of age and women 60-80 years of age, without known atherosclerotic cardiovascular disease (ASCVD) at baseline examination completed between January 2008 and June 2009. American College of Cardiology (ACC)/American Heart Association (AHA) lipid guideline recommendations were used to group participants into three statin benefit groups: 1) individuals without ASCVD or diabetes, 40-75 years of age with a low-density lipoprotein cholesterol (LDL-C) of 70-189 mg/dl, and estimated 10-year ASCVD risk of ≥7.5%; 2) individuals with diabetes, 40-75 years of age, and LDL-C 70-189 mg/dl; and 3) individuals with primary elevations of LDL-C ≥190 mg/dl. Presence of CAC or cPB was used to up- or down-classify participants for statin eligibility groups. Participants were classified from statin eligibility of optional to clear statin eligibility if CAC was ≥100 (or equivalent cPB). Participants were down-classified from statin-eligible to statin-ineligible if imaging revealed no CAC or cPB.

Results:

A total of 5,805 participants (mean age 69 years, 56% female) were included in this study. The majority of the cohort (86%) was statin-eligible because of an estimated 10-year ASCVD risk ≥7.5%; risk was ≥15% in 55% of participants. Over a median follow-up of 2.7 years, 91 participants were diagnosed with clinical coronary heart disease (CHD) and 138 experienced a cardiovascular event. CAC or cPB scores of 0 were common (32% and 23%, respectively) and associated with low event rates. With CAC-guided reclassification, specificity for CHD events improved 22% (p < 0.0001) without any significant loss in sensitivity, yielding a binary net reclassification index (NRI) of 0.20 (p < 0.0001). With cPB-guided reclassification, specificity improved 16% (p < 0.0001) with a minor loss in sensitivity (7%), yielding a NRI of 0.09 (p = 0.001). For cardiovascular events, NRI was 0.14 (CAC-guided) and 0.06 (cPB-guided). The positive NRIs were driven primarily by down-classifying the large subpopulation with CAC = 0 or cPB = 0.

Conclusions:

The investigators concluded that withholding statins in individuals without CAC or cPB could spare a significant proportion of elderly people from taking a pill that would benefit only a few. This individualized disease-guided approach is simple and easy to implement in routine clinical practice.

Perspective:

These data suggest that information on CAC or carotid arterial plaque may assist clinicians and their patients in determining whether to initiate statin therapy.

Clinical Topics: Diabetes and Cardiometabolic Disease, Clinical Topic Collection: Dyslipidemia, Geriatric Cardiology, Noninvasive Imaging, Prevention, Vascular Medicine, Lipid Metabolism, Nonstatins, Novel Agents, Statins

Keywords: Atherosclerosis, Carotid Stenosis, Coronary Artery Disease, Cholesterol, LDL, Diabetes Mellitus, Diagnostic Imaging, Dyslipidemias, Geriatrics, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Plaque, Atherosclerotic, Primary Prevention


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