Journal of the American College of CardiologyRandomized Controlled Trial - Multicenter Study
19 Nov 2024
Atrial fibrillation (AF) often remains undiagnosed, and it independently raises the risk of ischemic stroke, which is largely reversible by oral anticoagulation. Although randomized trials using longer term screening approaches increase identification of AF, no studies have established that AF screening lowers stroke rates.
To address this knowledge gap, the GUARD-AF (Reducing Stroke by Screening for Undiagnosed Atrial Fibrillation in Elderly Individuals) trial screened participants in primary care practices using a 14-day continuous electrocardiographic monitor to determine whether screening for AF coupled with physician/patient decision-making to use oral anticoagulation reduces stroke and provides a net clinical benefit compared with usual care.
GUARD-AF was a prospective, parallel-group, randomized controlled trial designed to test whether screening for AF in people aged ≥70 years using a 14-day single-lead continuous electrocardiographic patch monitor could identify patients with undiagnosed AF and reduce stroke. Participants were randomized 1:1 to screening or usual care. The primary efficacy and safety outcomes were hospitalization due to all-cause stroke and bleeding, respectively. Analyses used the intention-to-treat population.
Enrollment began on December 17, 2019, and involved 149 primary care sites across the United States. The COVID-19 pandemic led to premature termination of enrollment, with 11,905 participants in the intention-to-treat population. Median follow-up was 15.3 months (Q1-Q3: 13.8-17.6 months). Median age was 75 years (Q1-Q3: 72-79 years), and 56.6% were female. The risk of stroke in the screening group was 0.7% vs 0.6% in the usual care group (HR: 1.10; 95% CI: 0.69-1.75). The risk of bleeding was 1.0% in the screening group vs 1.1% in the usual care group (HR: 0.87; 95% CI: 0.60-1.26). Diagnosis of AF was 5% in the screening group and 3.3% in the usual care group, and initiation of oral anticoagulation after randomization was 4.2% and 2.8%, respectively.
In this trial, there was no evidence that screening for AF using a 14-day continuous electrocardiographic monitor in people ≥70 years of age seen in primary care practice reduces stroke hospitalizations. Event rates were low, however, and the trial did not enroll the planned sample size.(Reducing Stroke by Screening for Undiagnosed Atrial Fibrillation in Elderly Individuals [GUARD-AF]; NCT04126486).
Funding Support and Author Disclosures The Bristol Myers Squibb/Pfizer Alliance funded the GUARD-AF trial but was not involved in data collection, analysis, or interpretation; manuscript preparation; or decision to publish. Dr Lopes has received research grants or contracts from Amgen, Bristol Myers Squibb, GlaxoSmithKline, Medtronic, Pfizer, and Sanofi; has received funding for educational activities or lectures from Pfizer, Daiichi-Sankyo, and Novo Nordisk; and has received funding for consulting or other services from Bayer, Boehringer Ingelheim, Bristol Myers Squibb, and Novo Nordisk. Dr Atlas has received sponsored research support from Bristol Myers Squibb/Pfizer and the American Heart Association (18SFRN34250007); and has consulted for Boehringer Ingelheim, Bristol Myers Squibb, Fitbit, Pfizer, and Premier. Dr Go has received a research grant from Bristol Myers Squibb/Pfizer Alliance. Dr Lubitz is an employee of Novartis. Dr McManus has received grants or research support from Apple, Fitbit, Boehringer Ingelheim, Pfizer, Bristol Myers Squibb, and Flexcon; and has received consulting fees from Fitbit, NAMSA, Avania, and Heart Rhythm Society. Dr Rothberg is a consultant for Blue Cross Blue Shield Association. Prof Crosson is a former employee of iRhythm Technologies,. Dr Aronson and Mr Patlakh are employees of Bristol Myers Squibb. Ms. Mills is a former employee of Bristol Myers Squibb, Inc. Dr O’Brien has received institutional research funding from Pfizer. Dr Singer has received research support from Bristol Myers Squibb; and has consulted for the Bristol Myers Squibb, Pfizer, Medtronic, and Fitbit (Google). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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