AHA 2020: Active AF screening associated with significant improvement in clinical outcomes at three years


Three-year clinical outcomes of the mHealth Screening to Prevent Strokes—mSToPS—study evaluating silent, or previously undiagnosed, atrial fibrillation (AF) in moderate-risk individuals using Zio, the wearable ECG patch (iRhythm Technologies), were presented at the American Heart Association 2020 scientific sessions (AHA 2020, 13–17 November, virtual).

The study aimed to determine if participant-generated data available through a wearable ECG patch could improve the identification of AF relative to routine care and to determine if screening for AF by wearing Zio could improve clinical outcomes at three years after the initiation of screening. mSToPS evaluated the time to this first serious cardiac event, including stroke, systemic embolism, myocardial infarction, or death, via claims and Aetna membership data.

Data presented at AHA 2020 showed that in study participants AF was newly diagnosed in 11.4% of those actively monitored with Zio versus only 7.7% of the control group (a statistically significant 48% improvement). Additionally, the trial found the incidence rate of a cardiac event (stroke, myocardial infarction, systemic embolism, or death) was 8.4 per 100 person-years in people diagnosed with AF who underwent active monitoring, compared to the control group incidence rate of 13.8 per 100 person-years (a statistically significant improvement). This data demonstrates Zio’s detection of AF in moderate-risk patients supported the prevention of serious cardiac events after diagnosis, the study team concluded.

“The three-year results support the clinical value of early screening and targeted detection in moderate-risk populations,” said Steven Steinhubl, director of Digital Medicine at Scripps Research Translational Institute (San Diego, USA) and principal investigator of the study. “The study validates continued research into how to best monitor high-risk populations and confirms the value in discovering ways we can detect previously undiagnosed AF. It underscores the value of detecting AF as soon as possible to produce better patient outcomes.”

Furthermore, the study suggests that active monitoring with Zio also led to fewer hospitalisations for bleeding, the primary safety endpoint for the study (incidence rate of 0.32 per 100 person-years versus 0.71 per 100 person-years), while active monitoring led to fewer total hospitalisations (12.9 versus 18.9 per 100 person-years).

Ultimately, the mSToPS study found that active screening for AF, as part of a prospective, pragmatic, direct-to-participant and nationwide study, was associated with a significant improvement in clinical outcomes and safety at three years relative to routine care.

Steinhubl noted that limitations of the study include that the comparison between individuals choosing to participate in a randomised trial and an observational cohort may be biased by unmeasured confounding, adding that endpoints were based on claims data, limiting clinical follow-up to the duration of health plan enrolment and finally that treatment decisions were based on physician preference, and overall use of anticoagulants was low (<50%) in both cohorts.

“Through clinical validation with studies like mSToPS, iRhythm demonstrates the importance of shifting to preventative and more proactive care to catch undiagnosed atrial fibrillation and improve the lives of millions of people,” said Kevin King, CEO of iRhythm in a press release issued by the company highlighting the results.


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