October 20th, 2014
Are We Conducting Too Many Cardiac Stress Tests with Imaging?
CardioExchange’s Harlan M. Krumholz interviews Joseph A. Ladapo, lead investigator of a study about the use (and overuse) of cardiac stress testing in the United States. The article is published in the Annals of Internal Medicine and has been covered as a news story here on CardioExchange.
Krumholz: Please summarize your main findings .
Ladapo: We found that the use of cardiac stress testing in the U.S. has risen briskly during the past two decades; the use of imaging has grown particularly rapidly. The growth in cardiac stress testing can largely be explained by population and provider characteristics, but the use of imaging cannot. Notably, nearly one third of cardiac stress tests with imaging were probably inappropriate, because they were performed in patients who rarely benefit from imaging. Those tests — about 1 million each year — are associated with roughly half a billion dollars in annual healthcare costs and lead to about 500 people developing cancer in their lifetime because of radiation they received during that cardiac stress test.
Krumholz: How convinced are you that 1 million stress tests were inappropriate during the past two decades?
Ladapo: Using the 2014 ACCF/AHA Multimodality Appropriate Use Criteria, we estimate that probably about 1 million inappropriate stress tests with imaging are performed each year. We used liberal criteria to classify tests as appropriate, which we describe in detail in our supplementary appendix. For example, we considered the test appropriate if a patient had ischemic equivalents, CHD-risk equivalents (e.g., diabetes or peripheral artery disease), more than 2 CHD risk factors (e.g., a male smoker 50 years old), or a history of heart failure. We categorized the remaining tests as rarely appropriate because they were largely performed in low-risk patients. It’s likely that we actually underestimate the number of inappropriate stress tests.
Krumholz: What do you think ought to be done to improve testing?
Ladapo: This is clearly an area where more intensive testing is being used in patients for whom there is marginal value. I think the Choosing Wisely campaign will help reduce rates of inappropriate testing, along with the efforts of the ACCF/AHA. Clinical decision support for physicians would also be beneficial. Training medical residents and fellows about appropriate use of testing is an important step in helping to break the cycle. I think much of what we’re seeing in physician behavior is ecological, related to habit and familiar patterns.
Krumholz: Do you feel confident about your cancer estimate (harm) as a result of this screening?
Ladapo: We based our cancer estimates on excellent research from Dr. Rebecca Smith-Bindman and others at UCSF. Substantial uncertainty certainly exists in the research that has attempted to quantify the health harms from medical radiation, but we did our best to reflect what was supported in the scientific literature.
Krumholz: Is this an example of harm that cardiology has done inadvertently?
Ladapo: This is not just a “cardiology issue.” Primary care physicians order many of these tests. We have some work that shows that, in fact, PCPs are more likely to order an inappropriate cardiac stress test than cardiologists are. But it is definitely a big issue. We have an opportunity to reduce healthcare costs and the incidence of cancer by more appropriately selecting patients who benefit from imaging.
JOIN THE DISCUSSION
In light of Dr. Ladapo’s findings, share your observations about the inappropriate use of cardiac stress tests with imaging in clinical practice.