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Task Force: Nontraditional Markers Add Little to Heart Risk Assessment

Task Force: Nontraditional Markers Add Little to Heart Risk Assessment Too often, traditional methods for assessing risk of coronary heart disease in asymptomatic patients wrongly identify some healthy individuals as high risk, while missing impending problems in others. Overtreatment can mean unnecessary costs and increased anxiety for those diagnosed, while undertreatment can lead to myocardial infarctions and death. Researchers have therefore begun to examine nontraditional markers in hopes of finding more accurate screening tools. Measuring the ankle brachial index and other nontraditional risk assessments for coronary heart disease should not be used routinely, said the US Preventive Services Task Force. But analysis of these nontraditional markers has produced insufficient evidence to support their routine use, said the US Preventive Services Task Force in a recommendation statement released October 5 (US Preventive Services Task Force. Ann Intern Med. 2009;151[7]:474-482). The markers considered were high-sensitivity C-reactive protein (CRP), ankle-brachial index (ABI), leukocyte count, fasting blood glucose, periodontal disease, carotid intima-media thickness, coronary artery calcification score on electron-beam computed tomography (CAC), homocysteine, and lipoprotein(a). The gold standard for coronary heart disease risk assessment is the Framingham risk scoring system, which calculates an individual's 10-year percentage risk of myocardial infarction or coronary death based on age, gender, levels of total cholesterol and high-density lipoprotein cholesterol, smoking status, and blood pressure readings. Individuals are stratified to 3 risk levels: low (less than 10%), intermediate (10% to 20%), or high (more than 20%). Patients at high risk obviously need treatment, while those at low risk need only a congratulatory handshake and a reminder to maintain a healthy lifestyle. The problem for physicians comes with those at intermediate risk—“the Framingham's no-man's land,” said Ned Calonge, MD, MPH, the task force chair, in explaining why the group decided to study nontraditional coronary heart disease markers. “For the most part, we were able to say the risk factors were indeed associated with heart disease, but just saying a metric is associated with an outcome is in no way enough to say, ‘Let's use these to screen for disease,’” said Calonge. The task force did say that a supporting document it used in its analysis found strong evidence that CRP is associated with coronary heart disease events, as well as moderately consistent evidence that adding CRP to risk prediction models improves risk stratification among individuals in Framingham's intermediate-risk category. However, there is not yet sufficient evidence that reducing CRP levels prevents coronary heart disease events (Buckley DI et al. Ann Intern Med. 2009;151[7]:483-495). “The studies available [on CRP] make it difficult to determine how many people will be reclassified and benefit,” said Calonge, who is also the chief medical officer for the Colorado Department of Public Health and Environment in Denver. Task force recommendations tend to err on the side of caution, and physicians seeking additional information for treatment strategies do not necessarily embrace its findings. “The standard they are looking for is a study or a series of studies that tests strategies that would have a proven impact on medical outcomes, and the fact that a test might improve a predictive model is not good enough for the US Preventive Services Task Force,” said Philip Greenland, MD, professor of medicine at the Northwestern University Feinberg School of Medicine in Chicago. “I do not think this should be interpreted as meaning it should never be used in clinical practice. I think, on a selective basis, physicians have the discretion to say, ‘For this patient, I don't know what to do, and adding another test might help me’—and that is always the case in medicine.” The task force recommendations also run slightly counter to recommendations emanating from organizations such as the American Heart Association (AHA) and American College of Cardiology (ACC). Expert panels are working with these two groups to prepare updated guidelines, expected to be released next year, that address risk assessment as well as cholesterol and blood pressure findings. “One area of departure . . . is that the AHA/ACC may, in fact, offer a recommendation with the level of evidence cited, whereas the [task force], in general, is less inclined to recommend anything if there is not a strong evidence base,” said Sidney C. Smith Jr, MD, professor of medicine at the University of North Carolina School of Medicine in Chapel Hill, who is working with the expert panels. Michael S. Lauer, MD, director of the National Heart, Lung, and Blood Institute's Divisions of Prevention and Population Sciences and of Cardiovascular Diseases, said the task force has a well-deserved reputation for taking a rigorous look at the evidence. “Personally, I agree with that,” said Lauer. “One of the major problems we have with diagnostic testing is that with few exceptions, there is very little evidence that use [of such tests] results in improved health.” Calonge said he gets frustrated with advocates of nontraditional markers for assessing coronary heart disease risk because the tried-and-true treatments that will reduce risk continue to be underused. “There are thousands of life-years being left on the table daily because we are not following the recommendations that we already know work,” Calonge said. “If we put the resources into doing blood pressure screening and lipid screening and then follow it up with the appropriate therapies, we would save so many more lives than we would by incorporating CRP, ABI, or CAC.” http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA American Medical Association

Task Force: Nontraditional Markers Add Little to Heart Risk Assessment

Mitka, Mike
JAMA , Volume 302 (20) – Nov 25, 2009
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Publisher
American Medical Association
Copyright
Copyright © 2009 American Medical Association. All Rights Reserved.
ISSN
0098-7484
eISSN
1538-3598
DOI
10.1001/jama.2009.1678
Publisher site
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Abstract

Too often, traditional methods for assessing risk of coronary heart disease in asymptomatic patients wrongly identify some healthy individuals as high risk, while missing impending problems in others. Overtreatment can mean unnecessary costs and increased anxiety for those diagnosed, while undertreatment can lead to myocardial infarctions and death. Researchers have therefore begun to examine nontraditional markers in hopes of finding more accurate screening tools. Measuring the ankle brachial index and other nontraditional risk assessments for coronary heart disease should not be used routinely, said the US Preventive Services Task Force. But analysis of these nontraditional markers has produced insufficient evidence to support their routine use, said the US Preventive Services Task Force in a recommendation statement released October 5 (US Preventive Services Task Force. Ann Intern Med. 2009;151[7]:474-482). The markers considered were high-sensitivity C-reactive protein (CRP), ankle-brachial index (ABI), leukocyte count, fasting blood glucose, periodontal disease, carotid intima-media thickness, coronary artery calcification score on electron-beam computed tomography (CAC), homocysteine, and lipoprotein(a). The gold standard for coronary heart disease risk assessment is the Framingham risk scoring system, which calculates an individual's 10-year percentage risk of myocardial infarction or coronary death based on age, gender, levels of total cholesterol and high-density lipoprotein cholesterol, smoking status, and blood pressure readings. Individuals are stratified to 3 risk levels: low (less than 10%), intermediate (10% to 20%), or high (more than 20%). Patients at high risk obviously need treatment, while those at low risk need only a congratulatory handshake and a reminder to maintain a healthy lifestyle. The problem for physicians comes with those at intermediate risk—“the Framingham's no-man's land,” said Ned Calonge, MD, MPH, the task force chair, in explaining why the group decided to study nontraditional coronary heart disease markers. “For the most part, we were able to say the risk factors were indeed associated with heart disease, but just saying a metric is associated with an outcome is in no way enough to say, ‘Let's use these to screen for disease,’” said Calonge. The task force did say that a supporting document it used in its analysis found strong evidence that CRP is associated with coronary heart disease events, as well as moderately consistent evidence that adding CRP to risk prediction models improves risk stratification among individuals in Framingham's intermediate-risk category. However, there is not yet sufficient evidence that reducing CRP levels prevents coronary heart disease events (Buckley DI et al. Ann Intern Med. 2009;151[7]:483-495). “The studies available [on CRP] make it difficult to determine how many people will be reclassified and benefit,” said Calonge, who is also the chief medical officer for the Colorado Department of Public Health and Environment in Denver. Task force recommendations tend to err on the side of caution, and physicians seeking additional information for treatment strategies do not necessarily embrace its findings. “The standard they are looking for is a study or a series of studies that tests strategies that would have a proven impact on medical outcomes, and the fact that a test might improve a predictive model is not good enough for the US Preventive Services Task Force,” said Philip Greenland, MD, professor of medicine at the Northwestern University Feinberg School of Medicine in Chicago. “I do not think this should be interpreted as meaning it should never be used in clinical practice. I think, on a selective basis, physicians have the discretion to say, ‘For this patient, I don't know what to do, and adding another test might help me’—and that is always the case in medicine.” The task force recommendations also run slightly counter to recommendations emanating from organizations such as the American Heart Association (AHA) and American College of Cardiology (ACC). Expert panels are working with these two groups to prepare updated guidelines, expected to be released next year, that address risk assessment as well as cholesterol and blood pressure findings. “One area of departure . . . is that the AHA/ACC may, in fact, offer a recommendation with the level of evidence cited, whereas the [task force], in general, is less inclined to recommend anything if there is not a strong evidence base,” said Sidney C. Smith Jr, MD, professor of medicine at the University of North Carolina School of Medicine in Chapel Hill, who is working with the expert panels. Michael S. Lauer, MD, director of the National Heart, Lung, and Blood Institute's Divisions of Prevention and Population Sciences and of Cardiovascular Diseases, said the task force has a well-deserved reputation for taking a rigorous look at the evidence. “Personally, I agree with that,” said Lauer. “One of the major problems we have with diagnostic testing is that with few exceptions, there is very little evidence that use [of such tests] results in improved health.” Calonge said he gets frustrated with advocates of nontraditional markers for assessing coronary heart disease risk because the tried-and-true treatments that will reduce risk continue to be underused. “There are thousands of life-years being left on the table daily because we are not following the recommendations that we already know work,” Calonge said. “If we put the resources into doing blood pressure screening and lipid screening and then follow it up with the appropriate therapies, we would save so many more lives than we would by incorporating CRP, ABI, or CAC.”

Journal

JAMA – American Medical Association

Published: Nov 25, 2009

Keywords: advisory committees,risk assessment,heart

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