Based on its review of the evidence, the task force concluded that there is insufficient evidence to assess the balance of benefits and harms of screening for this condition. This is an “I” recommendation, and applies to adults 50 years or older who do not have signs or symptoms of AFib and do not have a history of transient ischemic attack or stroke.
“Unfortunately, there still is not enough evidence to know if screening for AFib helps to prevent strokes in older adults,” said task force member Gbenga Ogedegbe, M.D., M.P.H., in a USPSTF bulletin. “Since AFib is a risk factor for stroke and can go undetected, clinicians should use their best judgment to decide whether or not to screen people without signs or symptoms of AFib.”
Atrial fibrillation is the most common type of heart arrythmia. It contributes to roughly 158,000 deaths each year and causes about one in every seven strokes. The prevalence of AFib increases with age, from 0.2% in adults younger than 55 years to about 10% in those 85 years or older, with a higher prevalence in men. Additional risk factors for AFib include high blood pressure, diabetes, smoking and moderate to heavy alcohol use.
With only minor changes, the final recommendation statement is consistent with the task force’s August 2018 recommendation statement on the topic.
In the 2018 statement, the task force concluded at the time that the evidence was insufficient to assess the balance of benefits and harms of screening for AFib with electrocardiography.
Whereas the inclusion age for studies on the benefits and harms of screening for AFib was lowered to 50 years and older for the current recommendation, the inclusion age for studies in the 2018 recommendation applied to adults age 65 years and older.
The AAFP supported the 2018 recommendation.
To update the previous recommendation, the task force commissioned a systematic review of the evidence on the benefits and harms of screening for AFib in older adults, as well as the accuracy of screening tests, the effectiveness of screening tests to detect previously undiagnosed AFib compared with usual care, and the benefits and harms of anticoagulant therapy for the treatment of screen-detected AFib in older adults. For the current final recommendation, the task force expanded its review to include additional screening tests such as automated blood pressure cuffs, pulse oximeters, smartwatches and smartphone apps.
The review consisted of randomized clinical trials published in Medline, the Cochrane Library and trial registries through Oct. 5, 2020, along with bibliographies from retrieved articles, outside experts and literature surveillance conducted through Oct. 31, 2021. A total of 26 trials were included in the review.
Because of limited direct evidence, the task force could not give a definitive conclusion about screening benefits and harms.
The investigators found that while screening with intermittent or continuous ECG methods in primary care settings can detect more cases of previously unknown AFib, they also found that spot one-time ECG screenings may not detect more new cases of AFib than clinician reminders for pulse palpation (a practice considered usual care by the USPSTF). Furthermore, the investigators found that in low-prevalence settings, spot one-time screening tests could generate more false-positive than true-positive results, leading to patient anxiety, additional testing and possible initiation of unnecessary treatments.
The task force found no trials that reported on the benefits or harms of anticoagulant therapy in screen-detected populations. In patients with clinically detected AFib, however, evidence suggested that anticoagulant therapies such as warfarin or direct oral anticoagulants reduced the risk of outcomes such as first stroke and all-cause mortality compared with placebo. The same body of evidence suggested a possible increased risk for major bleeding, but estimates of this harm were not precise.
The task force also noted some research gaps that could be addressed through additional studies, including
A draft version of the recommendation statement was posted for public comment on the USPSTF website from April 20, 2021, to May 17, 2021.
In response to several comments, the USPSTF clarified that the “I” statement is not a recommendation against screening for AFib, but rather an indication of insufficient evidence to recommend for or against screening.
In response to the lowered inclusion age for studies on screening for AFib, the task force explained that it made the decision to include all potential evidence on screening for AFib. The task force added that lowering the inclusion age was not intended to dilute the evidence in older adults in any way, nor did it dilute the evidence.
A number of commenters suggested adding specific research gaps, such as determining optimal screening strategies and populations, or the association between subclinical AFib or AFib detected on consumer devices and stroke risk. In response, the USPSTF specified that understanding the stroke risk associated with AFib detected by consumer devices was a research need, and noted that screening with consumer devices was an included intervention in the current review.
The task force noted that it has published recommendation statements on several other factors related to the prevention of cardiovascular disease and stroke. These include
The AAFP’s Commission on Health of the Public and Science will review the task force’s final recommendation statement, final evidence summary and evidence review, and will then determine the Academy’s stance on the recommendation.