Almost 13,000,000 Americans have
coronary heart disease (CHD)
, a preventable disease. While screening for cardiovascular risk using conventional means (
, weight) has become commonplace, the beneficial effects of these screening results has been disappointing. Armed with this information, many patients still do not reduce their risk. There appears to be a need for a new risk prediction strategy.
One idea is to screen for the presence of cardiovascular disease itself, rather than its risk factors, in patients without symptoms. Electron beam tomography (EBT) is a relatively new procedure used to detect atherosclerotic deposits in the arteries that feed the heart, the presence of which indicate CHD. Physicians currently use EBT to motivate their patients to adopt healthier behaviors in the hope of preventing CHD. However, the effectiveness of this practice has not been established.
In a study published in the May 7, 2003
Journal of the American Medical Association
, researchers report that one year after EBT screening, asymptomatic patients had not changed their behaviors enough to significantly improve their cardiovascular risk.
About the Study
The researchers enrolled 450 men and women aged 39 to 45, between January 1999 and March 2001. They excluded anyone with a history of known CHD or
Each patient provided details of their personal and family medical history and smoking status, and then underwent measurements of height and weight, blood pressure, and cholesterol levels. Using these conventional risk factors, the researchers calculated the subjects’ predicted cardiovascular risk from the 10-year Framingham Risk Score (FRS) equation. Electron beam tomography was performed on all of the patients.
The researchers then randomly divided the patients into four groups:
EBT results were provided in an intensive care management (ICM) setting
EBT results were provided in a usual care setting
EBT results were withheld in an ICM setting
EBT results were withheld in a usual care setting
All participants were counseled about modifiable risk factors including
, sedentary lifestyle, smoking, high-fat diet, and glucose intolerance. For participants who were being told their EBT results, health participants explained whether their EBT results reflected atherosclerotic buildup in their arteries or not.
Usual care participants received dietary, smoking cessation, and exercise counseling as well as referral to a dietician or smoking cessation program if necessary. ICM participants were frequently contacted by nurses and dietitians who provided ongoing counseling tailored to the participants’ specific stage of behavioral change.
One year after EBT screening, researchers recalculated the participants’ 10-year Framingham Risk Scores.
One year after EBT screening, when the researchers compared the groups who received EBT results with those who did not, they found the average change in 10-year FRS score to be +0.30% versus +0.36%. This difference was not significant. The lack of effect of EBT results remained constant whether information was presented in an ICM or usual-care setting.
When comparing the group who received ICM with those who did not, they observed an average change in 10-year FRS score of –0.06% versus 0.74%, which represented a significant difference. After factoring in whether participants knew their EBT results, patients who received ICM were still significantly more likely to improve their 10-year FRS score compared to patients who received usual care.
How Does This Affect You?
Health professionals have speculated that presenting objective (in this case anatomical) evidence of heart disease might motivate patients to modify their health behaviors more than simply alerting them to their risk. This study showed that knowledge of EBT results did not spur patients to modify their behaviors enough to change their cardiovascular risk—at least not patients who were asymptomatic for CHD. However, it is possible that EBT would have a stronger effect on someone who is symptomatic for CHD.
The study did find that intensive case management was associated with decreased cardiovascular risk. This suggests that health professionals should focus on the aggressive identification and management of modifiable risk factors. In the meantime, more research should be done to determine whether ICM will result in decreased CHD mortality in the long term.
O’Malley PG, et al. Impact of electron beam tomography, with or without case management, on motivation, behavioral change, and cardiovascular risk profile: a randomized controlled trial.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a