Effect of a Home-Based Wearable Continuous ECG Monitoring Patch on Detection of Undiagnosed Atrial Fibrillation: The mSToPS Randomized Clinical Trial

Abstract

Importance: Opportunistic screening for atrial fibrillation (AF) is recommended, and improved methods of early identification could allow for the initiation of appropriate therapies to prevent the adverse health outcomes associated with AF.

Objective: To determine the effect of a self-applied wearable electrocardiogram (ECG) patch in detecting AF and the clinical consequences associated with such a detection strategy.

Design, setting, and participants: A direct-to-participant randomized clinical trial and prospective matched observational cohort study were conducted among members of a large national health plan. Recruitment began November 17, 2015, and was completed on October 4, 2016, and 1-year claims-based follow-up concluded in January 2018. For the clinical trial, 2659 individuals were randomized to active home-based monitoring to start immediately or delayed by 4 months. For the observational study, 2 deidentified age-, sex- and CHA2DS2-VASc-matched controls were selected for each actively monitored individual.

Interventions: The actively monitored cohort wore a self-applied continuous ECG monitoring patch at home during routine activities for up to 4 weeks, initiated either immediately after enrolling (n = 1364) or delayed for 4 months after enrollment (n = 1291).

Main outcomes and measures: The primary end point was the incidence of a new diagnosis of AF at 4 months among those randomized to immediate monitoring vs delayed monitoring. A secondary end point was new AF diagnosis at 1 year in the combined actively monitored groups vs matched observational controls. Other outcomes included new prescriptions for anticoagulants and health care utilization (outpatient cardiology visits, primary care visits, or AF-related emergency department visits and hospitalizations) at 1 year.

Results: The randomized groups included 2659 participants (mean [SD] age, 72.4 [7.3] years; 38.6% women), of whom 1738 (65.4%) completed active monitoring. The observational study comprised 5214 (mean [SD] age, 73.7 [7.0] years; 40.5% women; median CHA2DS2-VASc score, 3.0), including 1738 actively monitored individuals from the randomized trial and 3476 matched controls. In the randomized study, new AF was identified by 4 months in 3.9% (53/1366) of the immediate group vs 0.9% (12/1293) in the delayed group (absolute difference, 3.0% [95% CI, 1.8%-4.1%]). At 1 year, AF was newly diagnosed in 109 monitored (6.7 per 100 person-years) and 81 unmonitored (2.6 per 100 person-years; difference, 4.1 [95% CI, 3.9-4.2]) individuals. Active monitoring was associated with increased initiation of anticoagulants (5.7 vs 3.7 per 100 person-years; difference, 2.0 [95% CI, 1.9-2.2]), outpatient cardiology visits (33.5 vs 26.0 per 100 person-years; difference, 7.5 [95% CI, 7.2-7.9), and primary care visits (83.5 vs 82.6 per 100 person-years; difference, 0.9 [95% CI, 0.4-1.5]). There was no difference in AF-related emergency department visits and hospitalizations (1.3 vs 1.4 per 100 person-years; difference, 0.1 [95% CI, -0.1 to 0]).

Conclusions and relevance: Among individuals at high risk for AF, immediate monitoring with a home-based wearable ECG sensor patch, compared with delayed monitoring, resulted in a higher rate of AF diagnosis after 4 months. Monitored individuals, compared with nonmonitored controls, had higher rates of AF diagnosis, greater initiation of anticoagulants, but also increased health care resource utilization at 1 year.

Trial registration: ClinicalTrials.gov Identifier: NCT02506244.

Figure 1.. Participant Flow Diagram

^aInformation on why plan members chose not to participate is not available. ^bThe 161 ineligible participants includes 77 who were not health plan members or disenrolled before approval; 61 members who no longer met inclusion/exclusion criteria; and 23 with incomplete informed consent.

Figure 2.. Cumulative Rate of First Diagnosis of Atrial Fibrillation in the Actively Monitored and Observational Cohorts

The initial rapid increase in atrial fibrillation diagnoses seen in the diagnosed by patch group is due to those in that group who were randomized to the patch immediately. The second region of rapid rise in this curve, starting around 120 days, is primarily due to those in the delayed patch group. The immediate and delayed groups initiated monitoring at a median of 13 days and 102 days, respectively. Patch diagnosis of atrial fibrillation is defined as 30 seconds or more of atrial fibrillation or flutter detected by device. Clinical diagnosis defined as a single entry of an International Classification of Diseases, Ninth Revision code of 427.3, 427.31, or 427.32, or an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code of I48.0, I48.1, I48.2, I48.3, I48.4, I48.91, or I48.92.

Figure 3.. Distribution of Individual Percentage of Total Atrial Fibrillation Burden During Monitoring

Atrial fibrillation burden indicates percentage of total monitoring time in atrial fibrillation. A total of 69 participants had patch-detected atrial fibrillation. The median monitoring time was 26.5 days (interquartile range, 16.5-27.6 days).

Figure 4.. Days of Electrocardiogram Patch Wear Until a First Diagnosis of Atrial Fibrillation (AF) on the First or Second Patch and the Cumulative Wear Time Until Diagnosis

Patch 2 indicates patients who had AF on patch 2 only. Of the 1738 monitored participants, 1669 had no AF detected by patch. Of the 69 monitored participants with AF detected by patch, 21 had AF detected on patch 1 only, 6 of whom wore only 1 patch; 23 had AF detected on patch 2 only; and 25 had AF detected on both patches.