Screening for coronary artery calcium (CAC) with CT in patients at intermediate risk of coronary heart disease (CHD) is likely a cost-effective strategy for men, but not for women, according to a study to be published in the Oct. 11 issue of the Journal of the American College of Cardiology. An editorial in the same issue, however, said there is still too much uncertainty in the area of “personalized risk” strategies to justify a change in clinical practice guidelines and that a more comprehensive trial with CAC measurement is needed.
Bob J.H. van Kempen, Msc, of the Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues designed the study to assess the cost-effectiveness of screening for CAC in asymptomatic individuals at intermediate risk of CHD using CT. They noted that the current strategy for individuals at intermediate risk is generally to treat with drugs, but only when serum cholesterol or blood pressure reach certain levels. CT CAC screening may be able to identify those who would benefit from a more aggressive treatment.
Four strategies were evaluated by the researchers: current practice, current prevention guidelines for cardiovascular disease, CT screening for CAC and statin therapy for all individuals. The researchers then calculated quality-adjusted life years (QALYs), costs and incremental cost-effectiveness ratios by simulating asymptomatic individuals at intermediate risk of CHD over their remaining lifetime.
For men, CT screening was more effective and more costly than the other strategies, with an incremental cost-effectiveness ratio of $48,800/QALY gained, though the authors noted how slight changes in the simulations could alter the outcomes.
“In men, the incremental cost-effectiveness ratio for CT screening was just below the willingness-to-pay threshold of $50,000/QALY, and small changes in assumptions changed CT screening from being cost-effective to not cost-effective,” wrote van Kempen et al.
CT screening was not found to be cost-effective in women, according to the authors, even when including assumptions which were more favorable to the CT CAC screening strategy.
The editorial, written by Philip Greenland, MD, of Northwestern University in Chicago, and Tamar S. Polonsky, MD, of the University of Chicago, acknowledged the uncertainty in the area of CAC testing, and noted that testing could improve classification of risk by placing more individuals in extreme risk categories. However, they said more clinical trial evidence was needed before concluding that CAC testing should become a routine procedure and the results from van Kempen et al are not enough to warrant changing clinical practice guidelines.
“There was considerable uncertainty demonstrated in the sensitivity analyses, such that the optimal strategy could be routine CAC testing but might also be moderate dose ‘statin therapy’ for everyone not already taking statins,” wrote Greenland and Polonsky.
The editorialists added that the “treat all” option of administering statins may become more routine as guidelines are updated, making CAC testing less valuable as a result.
Greenland and Polonsky concluded that additional information is needed and that a screening trial with CAC measurement is overdue.