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Home-Based ECG Monitor Hikes New Afib Diagnoses

— mSToPS study called example of innovative trial design

Last Updated July 13, 2018
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Patients wearing a continuous electrocardiogram (ECG) monitoring patch had more new atrial fibrillation (Afib) diagnoses and were tied to more healthcare utilization, according to findings from the mHealth Screening to Prevent Strokes (mSToPS) randomized trial.

Members of the Aetna Fully Insured Commercial and Medicare Advantage populations who were randomized to a head start in iRhythm Zio monitoring -- receiving the adhesive skin patch immediately upon recruitment -- had a higher incidence of a new Afib diagnosis at 4 months, when a second study arm just started receiving their patches (3.9% versus 0.9%, absolute difference 3.0%, 95% CI 1.8 to 4.1%), found researchers led by Steven Steinhubl, MD, of Scripps Translational Science Institute in La Jolla, Calif.

Action Points

  • Note that this randomized trial found that the use of an ECG-monitoring patch was associated with diagnosis of atrial fibrillation and increased healthcare utilization.
  • Be aware that the study did not demonstrate whether clinical outcomes differed based on receipt or non-receipt of the patch.

Altogether, those randomized to have immediate or delayed monitoring also had more new Afib diagnoses at 1 year compared with matched controls in an observational analysis (6.7 versus 2.6 per 100 person-years, absolute difference 4.1%, 95% CI 3.9 to 4.2%), the researchers reported online in the .

Their mSToPS data were previously presented at the American College of Cardiology annual meeting.

During the first year of the study, active monitoring was also associated with more patients, as follows:

  • Initiating anticoagulant therapy (5.7 versus 3.7 per 100 person-years, absolute difference 2.0%, 95% CI 1.9 to 2.2%)
  • Making outpatient cardiology visits (33.5 versus 26.0 per 100 person-years, absolute difference 7.5%, 95% CI 7.2 to 7.9%)
  • Visiting primary care (83.5 versus 82.6 per 100 person-years, absolute difference 0.9%, 95% CI 0.4 to 1.5%)

Whether patients used the Zio apparently made no difference in Afib-related emergency department visits and hospitalizations, however (1.3 versus 1.4 per 100 person-years, absolute difference 0.1%, 95% CI -0.1% to 0).

"Most individuals who had Afib diagnosed by ECG patch had a relatively low burden of paroxysmal Afib; only a small percentage of incident cases (3/65 [4.6%]) were found to have persistent Afib," the authors wrote. "These results suggest that spot checking for Afib, whether by a random pulse check for irregularity or obtaining a brief ECG, would likely miss most individuals with undiagnosed Afib.

"A new diagnosis of Afib would never be considered a normal finding and, even when asymptomatic, is strongly associated with the development of clinical Afib," the researchers continued. "Early recognition could encourage the implementation of strategies to prevent progression, such as treatments of sleep apnea or morbid obesity. However, currently, the primary clinical question for screen-detected Afib revolves around the risks and benefits for the initiation of anticoagulants."

The Zio is an FDA-approved water-resistant patch that can be worn up to 2 weeks during routine activity. In the study, the active monitoring patients received two patches and wore each for an average of 11.7 days.

What made mSToPS special was its "direct-to-participant" recruitment of patients by email or direct mail, with the screening and consent processes also performed digitally, Steinhubl et al explained. Follow-up was based on claims.

Writing in an , Eric Peterson, MD, MPH, of Duke University Medical Center in Durham, N.C., and Robert Harrington, MD, of Stanford University in California, said the trial "represents an innovative example of the potential (and challenges) inherent in a pragmatic IT [information technology] trial."

The gold standard in clinical studies, the randomized clinical trial (RCT), is weakened by often selectively enrolling patients and the time and cost needed to invest in it, the editorial noted. "Researchers need to make RCTs more efficient, patient-centric, and pragmatic -- ready to take on the coming tsunami of new health technologies."

In the study, patients who were eligible for mSToPS were older individuals and those with at least one comorbidity. Only 65.4% of those who passed screening and got randomized (n=2,659) actually put on their continuous ECG monitoring device. Out of the more than 100,000 patients invited to participate, only 1.7% were successfully recruited and monitored. Individuals who chose to participate were younger, more often men, and had fewer comorbidities than those who chose not to participate.

A separate cohort of eligible individuals who did not get active monitoring were used as matched controls (n=3,476) for the 1-year comparison.

"While innovative, their resultant observational comparison provides less definitive conclusions than would have come from an RCT," the editorial by Peterson and Harrington continued. "The diagnostic value of the patch may have been greater had the population studied been enriched for other clinical Afib risk markers not available in claims data."

In a recent interview with 鶹ý, Alfred Bove, MD, PhD, of Temple University in Philadelphia, noted in general that device screening trials aren't looking at important endpoints: "In fact, there's no evidence from implantable cardiac monitors, patch monitors, or other such devices to prove that the extra detection of brief or silent Afib actually translates into clinical benefit."

In addition, other research has shown that looking deeper and longer for Afib after ischemic strokes regardless of apparent cause invariably finds more cases.

The mSToPS investigators have follow-up planned out to 3 years, Steinhubl et al said.

In , Benjamin Steinberg, MD, MHS, of the University of Utah Health Sciences Center in Salt Lake City, and Jonathan Piccini, MD, MHS, also of Duke University Medical Center, noted that cost differences in particular between groups will be informative.

"In summary, the mSToPS trial ... provides strong support for the use of 2 weeks of continuous rhythm monitoring to screen for Afib in at-risk populations, given the detection rate of up to 5% at 4 months."

  • author['full_name']

    Nicole Lou is a reporter for 鶹ý, where she covers cardiology news and other developments in medicine.

Disclosures

mSToPS was funded by grants from Janssen, the National Institutes of Health, and the Qualcomm Foundation.

Steinhubl reported additional support from DynoSense, EasyG, Spry Health, and Striiv.

Peterson reported relationships with Verily, Akili, Reflexion Health, and Livogo.

Harrington reported relationships with Apple, Sanofi, AstraZeneca, Portola, Janssen, Bristol-Myers Squibb, Novartis, CSL, The Medicines Company, Bayer, Amgen, Element Science, Gilead, MyoKardia, WebMd, Signal Path, Scanadu, the American Heart Association, and Stanford Health Care.

Primary Source

Journal of the American Medical Association

Steinhubl SR, et al "Effect of a home-based wearable continuous ECG monitoring patch on detection of undiagnosed atrial fibrillation: The mSToPS randomized clinical trial" JAMA 2018; 320(2): 146-155.

Secondary Source

Journal of the American Medical Association

Steinberg BA, Piccini JP "Screening for atrial fibrillation with a wearable device" JAMA 2018; 320(2): 139-141.

Additional Source

Journal of the American Medical Association

Peterson ED, Harrington RA "Evaluating health technology through pragmatic trials: Novel approaches to generate high-quality evidence" JAMA 2018; 320(2): 137-138.