iRhythm Technologies, Inc. (NASDAQ:IRTC), a leading digital health care company focused on creating trusted solutions that detect, predict, and prevent disease, today announced the presentation and publication of the GUARD-AF (ReducinG stroke by screening for UndiAgnosed atRial fibrillation in elderly inDividuals) randomized clinical trial at the European Society of Cardiology (ESC) Congress 2024. The trial was sponsored by Bristol-Myers Squibb-Pfizer Alliance and iRhythm provided the Zio XT patch ECG long-term continuous monitoring (LTCM) monitor used in the interventional (screening) arm of the study.

GUARD-AF was a prospective, parallel-group, randomized controlled trial designed to test whether screening for AF in people aged ≥70 years using an on-label Zio XT 14-day single-lead LTCM could identify patients with undiagnosed AF and reduce stroke. Participants were randomized 1:1 to screening with Zio XT LTCM or usual care. The primary efficacy and safety outcomes were hospitalization due to all-cause stroke and bleeding, respectively.

During a median follow-up of 15 months in 11,905 enrolled patients from 149 primary care sites in the US (5,952 assigned to screening), the study found that Zio XT LTCM led to an increase in new diagnosis of AF vs usual care (5.0 vs 3.3%) through the end of follow-up. There was no significant difference between groups in incidence of the primary endpoint of stroke hospitalization, although event rates were low and the trial was stopped before achieving enrollment of the planned total of 52,000 patients during the COVID-19 pandemic2, thereby reducing statistical power. Findings were presented by Dr. Renato Lopes, Professor of Medicine at the Duke Clinical Research Institute and Duke University, at the ESC Congress on September 1 and simultaneously published in two tandem manuscripts in the Journal of the America College of Cardiology (JACC)3 and the JACC: Clinical Electrophysiology.