USPSTF advises against ECG screening for low-risk adults
The USPSTF also concluded that the current evidence is insufficient to assess the balance of benefits and harms of screening with resting or exercise ECG for the prediction of CHD events in asymptomatic adults at intermediate or high risk for CHD events.
CHD is the leading cause of death in the U.S., with more than 406,000 deaths (16.8 percent of all deaths) reported in 2007, according to the authors. One-third of all deaths among persons older than 35 years results from CHD. In addition to mortality, CHD causes significant morbidity; its prevalence approaches 50 percent among middle-age U.S. men and 33 percent among middle-age U.S women. The annual financial cost of CHD was expected to exceed $300 billion in 2010.
The USPSTF makes recommendations about the effectiveness of clinical preventive services for patients without related signs or symptoms. It bases its recommendations on the evidence of both the benefits and harms of the service, and an assessment of the balance. The USPSTF did not consider the costs of providing a service in this assessment. The task force noted that “clinical decisions involve more considerations than evidence alone.” Similarly, the USPSTF said that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.
To update its previous recommendation, the task force reviewed new research published since its 2004 recommendation to compare the benefits and harms of screening asymptomatic adults with ECG with no screening at reducing the risk for CHD events. The researchers also looked at how identifying high-risk individuals affected treatment to reduce risk, and the accuracy of risk stratification.
In deciding whether to screen with resting or exercise ECG in asymptomatic adults who are at intermediate or high risk for CHD events, the task force said that clinicians should consider the following:
- Potential preventable burden. While there is insufficient evidence to determine whether screening adults at increased risk is beneficial, those who are at intermediate risk for CHD events have the greatest potential for net benefit from ECG screening. Reclassification into a higher-risk category might lead to more intensive medical management that could lower the risk for CHD events, but it might also result in harms, including medication adverse effects such as gastrointestinal bleeding and hepatic injury. The risk-benefit tradeoff would be most favorable if patients can be accurately reclassified from intermediate to high risk. Patients who are already at high risk should receive intensive risk factor modification, regardless of ECG findings, while those who are already classified as low risk are unlikely to benefit, regardless of ECG findings. Although some exercise programs initially screen asymptomatic participants with exercise ECG, there is not enough evidence to determine the balance of benefits and harms of this practice.
- Potential harms. In all risk groups, an ECG abnormality (as a result of a true- or false-positive test) can lead to invasive confirmatory testing and treatments that have the potential for serious harm, including unnecessary radiation exposure and the associated risk for cancer. Studies report that up to 3 percent of asymptomatic patients with an abnormal exercise ECG test receive angiography and up to 0.5 percent undergo revascularization, even though it has not been demonstrated that revascularization results in a reduction of CHD events in asymptomatic individuals. Angiography and revascularization are associated with risks, including bleeding, contrast-induced nephropathy and allergic reactions to the contrast agent.
- Current practice. Screening with resting or exercise ECG in low-risk patients is not recommended by any organization. However, evidence on current clinical use of screening for CHD with resting or exercise ECG in asymptomatic patients is sparse. Anecdotally, it is performed with some frequency.
- Costs. While the cost of resting ECG may be low, the downstream costs of resulting diagnostic testing and treatments can be significant.
As in 2004, the USPSTF continues to recommend against screening in low-risk adults, and found insufficient evidence on screening in adults at increased risk. The current recommendation differs from the 2004 recommendation in the screening interventions that were reviewed; the current recommendation excluded evidence on electron-beam computed tomography because it is addressed in another USPSTF recommendation published in 2009.