The use of coronary artery calcium (CAC) discriminates mortality risk and allows physicians to reclassify risk in the elderly, despite their limited life expectancy, according to a study in the July 1 issue of the Journal of the American College of Cardiology.
Paolo Raggi, MD, from the division of cardiology and the department of medicine at Emory University School of Medicine in Atlanta, and colleagues assessed the all-cause mortality in 35,388 patients (3,570 were ≥70 years old at screening, 50 percent of whom were women) after a mean follow-up of approximately 5.8 years.
The researchers found that risk factors and CAC were more prevalent in older patients.
Overall survival was 97.9 percent at the end of follow-up. Mortality increased with each age decile with a relative hazard of 1.09, and rates were greater for men than women, according to the investigators.
Increasing CAC scores were associated with decreasing survival across all age deciles, the authors wrote. Survival for a <40-year and ≥80-year-old man with a CAC score ≥400 was 88 percent and 19 percent (95 percent and 44 percent for a woman), respectively.
Among 20,562 patients with no CAC, Raggi and colleagues found that the annual mortality rates ranged from 0.3 percent to 2.2 percent for patients age 40 to 49 years or ≥70 years. The use of CAC allowed the researchers to reclassify more than 40 percent of the patients ≥70 years old more often by excluding risk (i.e., CAC <400) in those with >three risk factors, the investigators wrote.
They concluded that because “risk factors lose prediction power with advancing age, and the absence of CAC matches a low risk, it may be appropriate to mitigate prevention efforts in elderly patients with no evidence of subclinical atherosclerosis.”