by Lara C. Pullen, PhD July 06, 2015 original source: http://www.medscape.com/viewarticle/847546
The extent of coronary artery calcification (CAC) is an accurate predictor of 15-year mortality in asymptomatic individuals, according to a new study published online July 6 in the Annals of Internal Medicine.
Leslee J. Shaw, PhD, from Emory University School of Medicine in Atlanta, Georgia, and colleagues found that individuals without CAC had 15-year all-cause mortality rate of 3%. In contrast, overall mortality increased to 28% for individuals with CAC scores of 1000 or higher (P < .001).
The research builds on previous reports on the prognostic value of CAC scores. Many studies have identified an excess hazard for worsening clinical outcomes in individuals with high scores. Most of the studies, however, have been relatively short term.
The current study, with a cohort of 9715 adults, is noteworthy because it is based on a 15-year follow-up. In addition, the use of all-cause mortality as an endpoint expands the study beyond traditional cardiovascular disease outcomes and adds another component to a potential calculation of risk.
“The Framingham risk score is a well-established method for estimating 10-year CHD risk, whereas we applied CAC scoring to estimate 15-year all-cause mortality. A reasonable question is whether overlap exists between these scores. Age is strongly related to CAC, with incidence increasing in older patients; however, our data note substantive risk reclassification (that is, [net reclassification improvement] > 0.20) in patients with CAC and risk factors beyond age and other cardiac risk factors,” the authors write.
The researchers explain, however, that their data do not point toward targeted treatment of patients with high CAC scores. “Our study had a long duration of follow-up with clinical outcome data available only on all-cause mortality. Because we are presenting observational data, causality with regard to influencing outcome cannot be inferred.”
The study can be used, however, to further the discussion as to whether or not routine CAC scanning provides any benefit to society.
One coauthor reports that she has stock holdings/options in Eli Lilly and Pfizer. Another coauthor reports that she has stock holdings in Pfizer. The other authors have disclosed no relevant financial relationships.
Ann Intern Med. Published online July 6, 2015.