Early detection of atrial fibrillation with a wearable patch may help reduce strokes
Study finds that wearing a heart rhythm-recording patch for early detection of AFib was associated with a lower rate of stroke, heart attack, or blood clots three years later
October 05, 2021
LA JOLLA, CA—The 3-year observational results of a novel, direct-to-participant clinical trial, found that people who wore heart rhythm-recording patches for early detection of atrial fibrillation (AFib) had a lower rate of stroke, heart attack, or other major vessel-blocking blood clots three years later, compared to a control group of people whose AFib was diagnosed in the ordinary way at doctors’ offices or hospitals.
The results, published in PLoS One, also include the finding that there was a strikingly high chance of these cardiovascular events in the four weeks surrounding ordinary AFib diagnoses, versus virtually zero chance with diagnoses via the patch.
“On the whole our results support the idea that screening for AFib with wearable tech, in an appropriately defined population, might be able to meaningfully reduce the risks of strokes and other adverse cardiovascular events—and that that issue should be resolved in more conclusive trials,” says study senior author Steven Steinhubl, MD, an associate professor at the Scripps Research Translational Institute.
AFib is the most commonly diagnosed heart arrhythmia. Researchers estimate that between three and six million older adults in the U.S. have it, although studies suggest that up to 30 percent of cases are undiagnosed. The abnormal heartbeat rhythm of AFib disrupts cardiac blood flow and promotes clot formation, and AFib is a risk factor for strokes, heart attacks, blood clots outside the brain and heart, and heart failure.
AFib is often diagnosed only after a cardiovascular emergency has occurred, which hints that early detection would allow patients to avoid such emergencies by adopting preventive measures including blood thinner medicines and a healthier diet.
Steinhubl and colleagues set up the mHealth Screening To Prevent Strokes (mSToPS) trial six years ago to investigate this question in a pragmatic, patient-centric way, teaming with the study sponsor, Janssen Pharmaceuticals, along with health insurer Aetna to gather participants, and iRhythm, the maker of a wearable electrocardiogram patch called the Zio®XT. There were 1,738 participants who underwent active monitoring. Results after one year, which were published in 2018, showed that monitoring with the patch was associated with significantly more AFib diagnoses, as well as more initiation of anticoagulant medicines.
The new paper focuses on clinical outcomes, including cardiovascular outcomes after three years. The main finding was that in comparison to matched non-participants from the Aetna database, those who participated in the trial and wore a patch had a 20 percent lower rate of cardiovascular adverse events, defined as any stroke, heart attack, or other major vessel-blocking blood clot (systemic embolism). However, this prespecified primary endpoint can only be considered exploratory because the rate of AFib remained significantly different at three years between the two cohorts, which was not hypothesized to be the case.
The researchers also found that the clinical circumstances surrounding AFib diagnosis were radically different depending on how it was diagnosed. Among those diagnosed in the ordinary way, in doctors’ offices and hospitals, 6.6 percent had a stroke, 10.2 percent were newly diagnosed with heart failure, 9.2 percent had a heart attack, and 1.5 percent had a systemic embolism, in the four weeks surrounding their diagnosis. By contrast, those diagnosed via screening with the patch included only a single case of newly diagnosed heart failure and no heart attacks, strokes, or emboli in the four-week period surrounding the diagnosis.
As Steinhubl emphasizes, the study as designed could not show conclusively that patch-based screening improves health outcomes. For example, the patch-wearing group was actively recruited into the study—and might thus have been more motivated to protect their health—whereas the comparison group was not. But he adds that AFib is such a strong risk factor for clot-related problems that early detection and treatment likely would have benefits for many patients.
“It’s a hard thing to show conclusively,” he says. “We need to learn more about whom to screen and when to screen in order to prevent, with anticoagulants or even simple lifestyle interventions, what is obviously a large risk of bad outcomes in people who wait to be diagnosed clinically.”
“Three-year clinical outcomes in a nationwide, observational, siteless clinical trial of atrial fibrillation screening - mHealth Screening to Prevent Strokes (mSToPS)” was co-authored by Steven Steinhubl, Jill Waalen, Lauren Ariniello, Gail Ebner, Katie Baca-Motes, and Eric Topol, of Scripps Research Translational Institute; Anirudh Sanyal and Alison Edwards of Healthagen LLC; Robert Zambon of Janssen Research and Development; and Troy Sarich of Johnson & Johnson.
The research was supported by a research grant from Janssen Pharmaceuticals. Additional support was provided by a National Institutes of Health’s National Center for Advancing Translational Sciences grant (UL1TROO1114) and a grant from Qualcomm Foundation.
For more information, contact press@scripps.edu