Hello, everyone. I'm Dr Kenny Lin, a family physician at Georgetown University Medical Center in Washington, DC, and I blog at Common Sense Family Doctor.
Recently, I was contacted by a continuing medical education provider that was looking to develop content on screening for atrial fibrillation. Identifying people with asymptomatic atrial fibrillation might make sense for pharmaceutical companies, because it would probably lead to more people being prescribed pricey brand-name oral anticoagulants to prevent stroke. But does it make medical sense to do so?
More than 2 years ago, a JAMA viewpoint argued that screening older patients for atrial fibrillation could have substantial benefits because undiagnosed atrial fibrillation contributes to a significant proportion of cryptogenic strokes, screening can be easily implemented in primary care settings, and studies of incidentally detected atrial fibrillation suggest that treatment reduces stroke and mortality rates to a similar degree as in symptomatic persons. More recently, the same authors asserted that atrial fibrillation satisfies all items in the classic World Health Organization criteria for appraising the validity of a screening program.
However, others have sounded a note of caution. Drs Adam Cifu and Vinay Prasad have argued that "the benefit of treating atrial fibrillation that is found after a more aggressive search for the arrhythmia will probably be lower than we are accustomed to...[while] the risks and costs of anticoagulation will be the same." Cardiologist and Medscape columnist John Mandrola has also expressed concern that the proliferation of handheld and wearable ECG devices will contribute to an epidemic of overdiagnosis and unnecessary treatment.
What does the evidence say? A 2016 Cochrane review identified only a single randomized, controlled trial (RCT) that compared systematic screening for atrial fibrillation with usual practice. As would be expected, participants in the screening arm were more likely to be diagnosed with atrial fibrillation and started on oral anticoagulation therapy. However, the trial will not report patient-oriented outcomes, such as stroke prevention and gastrointestinal and cerebral hemorrhaging, until 2019 at the earliest.
The US Preventive Services Task Force recently released a draft recommendation statement on ECG screening for atrial fibrillation that concluded there is currently insufficient evidence to assess the balance of benefits and harms. Although they found no RCTs supporting the benefits of screening, they identified one trial that provided information on harms. About 15,000 adults aged 65 and older from general practices in England participated in this study.[7,8] More than 2500 participants had false-positive results, and about 2000 of them reported anxiety as a result.
This isn't to say that these tradeoffs aren't worthwhile—we tolerate several hundred false-positive screening mammograms to prevent one death from breast cancer in the United States, after all—but it does argue for waiting for the data so that we know for certain whether screening for atrial fibrillation prevents enough strokes and/or deaths to outweigh the harms. In the meantime, family physicians should continue to adhere to evidence-based treatment practices for persons with known atrial fibrillation, as outlined in a recent guideline that I coauthored for the American Academy of Family Physicians.
This has been Dr Kenny Lin, for Medscape Family Medicine. Thank you for listening.
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Cite this: Atrial Fibrillation: Is Screening a Good Idea? - Medscape - Feb 14, 2018.