CORRESPONDENCE: LETTER TO THE EDITOR
Don't Throw the Baby Out With the Bath Water
Bruce H. Brundage, MD*
* Medical Director, Heard Institute of the Cascades, 2500 N.E. Neff Road, Bend, Oregon 97701 (Email: Bhbrundage{at}cascadehealthcare.org).
Budoff et al. (1) have presented important information from the MESA (Multi-Ethnic Study of Atherosclerosis) trial about the interpretation of coronary artery calcium (CAC) scores. There has been some controversy as to how to interpret what constitutes a high-risk score. Is the age/sex/ethnicity adjusted percentile score or the absolute total score best? To me it seems to depend on what is your question about high risk. In the Budoff et al. (1) article, clearly the authors are interpreting high risk as the risk for a cardiac event in the short term (46 months). However, to the clinician and patient, it is of great importance to determine which individuals are at high risk in the longer term (i.e., decades).
The authors cite an example of a 50-year-old Hispanic woman who has a CAC score of 25, which places her in the 95th percentile for age/sex/ethnicity compared with an 83-year-old white man with a CAC of 1,572, which places him in the 72nd percentile for his age/sex/ethnicity. The main point of the article is that although the man has a lower percentile than the woman, he is at much greater risk for a short-term cardiac event. No argument, the greater the atherosclerotic burden the greater the short-term risk. However, I think it is important to recognize that the percentile score has clinically useful information that the absolute score does not. The fact that the 50-year-old woman's score places her in the 95th percentile for age/sex/ethnicity means she will reach the high-risk score of 400 at a much earlier age, probably within 15 years (2), compared with many of her peers, who had the more likely score of 0 and will take 35 years or longer to achieve a high-risk score. I believe this is very useful information for the physician and the patient and will significantly impact decision-making about diet, lifestyle, and medications. In other words, I think we and our patients are interested in both the short- and long-term risk. If I am a 39-year-old white man with a score of 50, I certainly would want to know that I am likely to have a high-risk score within 10 years (3).
Knowing both short- and long-term risk is useful. The percentile score predicts the long-term risk and tells us how soon, untreated, we will reach a high-risk score. The absolute score represents the atherosclerotic burden currently present and therefore best predicts the short-term risk.
However, the Budoff et al. (1) article and the accompanying editorial seem to downplay the importance and value of the percentile score in their enthusiasm to identify the most powerful predictor of short-term risk. The data presented support their enthusiasm, but please don't throw the baby out with the bath water.
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1. Budoff MJ, Nasir K, McClelland RL, et al. Coronary calcium predicts events better with absolute calcium scores than age-sex-race/ethnicity percentiles: MESA (Multi-Ethnic Study of Atherosclerosis) J Am Coll Cardiol 2009;53:345-352.[Abstract/Free Full Text]2. McClelland RL, Chung H, Detrano R, Post W, Kronmal. Distribution of coronary artery calcium by race, gender and age: results from the Multi-Ethnic Study of Atherosclerosis (MESA) Circulation 2006;113:30-37.[Abstract/Free Full Text] 3. Hoff JA, Chomka EV, Kranik AJ, Daviglus M, Rich S, Kondos GT. Age and gender distributions of coronary artery calcium detected by electron beam tomography in 35,246 adults Am J Cardiol 2001;87:1335-1339.[CrossRef][Web of Science][Medline]
Related Article
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Reply
- Matthew J. Budoff and Khurram Nasir
J. Am. Coll. Cardiol. 2009 54: 574-575.
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