CCTA Leads to More Procedures, More Costs in Older Patients

Reed Miller

November 28, 2011

November 24, 2011 (Stanford, California) - Coronary computed tomography angiography (CCTA) scans in older patients leads to more follow-up testing and downstream costs than stress testing, a new study published last week in the Journal of the American Medical Association shows [1].

Many previous studies have shown that CCTA has high sensitivity (85–99%), but only moderate specificity (82–95%) for detecting significant coronary disease, compared with the gold standard of invasive coronary angiography, study author Dr Mark Hlatky (Stanford University, CA) explains.

Because the test is so sensitive, CCTA might reduce follow-up testing in some patient populations by excluding people who have no significant coronary disease. On the other hand, because it isn't very specific, CCTA may lead to more tests in some types of patients because it detects many atherosclerotic plaques that turn out to be hemodynamically insignificant, Hlatky explained to heartwire . The purpose of this study was to see which hypothesis is true for older patients and how it affects downstream costs.

We can't say whether the tests and procedures that were done were appropriate or inappropriate . . . we just know that these things were done.

"A lot of people had expected that it would be cost-lowering to use CCTA, not cost increasing," he said. "A lot of people have studied this in younger populations and found less incidence of testing afterwards, but our data show something different." Most previous studies of the impact of CCTA on costs were conducted in populations in their 50s, while the average age of patients in this study was about 75. "There may be more inconclusive tests or tests that are suggestive of disease in the older population, and they lead to more investigation and, in many cases, more procedures."

Sensitivity is probably going to be more of an issue in older patients "because completely normal vessels may be a lot less likely in somebody who is 75 than in somebody who is 45. They ought to be," Hlatky said. "Like all tests, it depends on the population you're applying it to."

Study Reviewed Nonemergent, Noninvasive Tests

The study examined Medicare claims data from a 20% random sample of 282 830 Medicare fee-for-service beneficiaries from 2005 to 2008 who were 66 years or older. All of the patients received nonemergent, noninvasive testing for coronary disease, but had no claims for coronary disease in the preceding year. Costs of cardiac catheterization, coronary revascularization, acute myocardial infarction, all-cause mortality, coronary disease-related Medicare spending, and total Medicare-spending were followed for 180 days.

CCTA scanning in these patients was associated with an increased likelihood of subsequent cardiac catheterization compared with stress myocardial perfusion scintigraphy (22.9% vs 12.1%; p<0.001). CCTA also led to more percutaneous coronary interventions (7.8% vs 3.4%; p<0.001), and more coronary artery bypass graft surgeries (3.7% vs 1.3%; p<0001) than stress testing.

Costs Climb in CCTA-Scanned Patients

Because it led to more testing, Medicare costs for the CCTA-scanned patients were an average of $4200 higher than that of patients just undergoing stress testing (p<0.001), which was almost entirely attributable to payments for claims related to coronary disease. However, CCTA was associated with similar chances of all-cause mortality (1.05% vs 1.28%; p=0.32) and a slightly lower chance of hospitalization for acute myocardial infarction (0.19% vs 0.43%; p=0.04).

Hlatky pointed out: "We don't have a lot of clinical details so we can't say whether the tests and procedures that were done were appropriate or inappropriate . . . we just know that these things were done. We're not sure exactly why . . . and we don't know if that was a good thing or a bad thing."

Hlatky said that the next step will be to follow these patients longer than six months to see if adverse events or other "hard outcomes" are different in patients scanned with CCTA vs those undergoing only stress testing. He added that these retrospective data "underscore the importance of some of the ongoing trials like PROMISE that will look at this in an experimental way and measure a lot of important outcomes as well as the cost."

This study was funded by the American Heart Association. The authors report no conflicts of interest.


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