Screening for Atrial Fibrillation in the Older Population: A Randomized Clinical Trial

Abstract

Importance: Atrial fibrillation (AF) is a major cause of preventable strokes. Screening asymptomatic individuals for AF may increase anticoagulant use for stroke prevention.

Objective: To evaluate 2 home-based AF screening interventions.

Design, setting, and participants: This multicenter randomized clinical trial recruited individuals from primary care practices aged 75 years or older with hypertension and without known AF. From April 5, 2015, to March 26, 2019, 856 participants were enrolled from 48 practices.

Interventions: The control group received standard care (routine clinical follow-up plus a pulse check and heart auscultation at baseline and 6 months). The screening group received a 2-week continuous electrocardiographic (cECG) patch monitor to wear at baseline and at 3 months, in addition to standard care. The screening group also received automated home blood pressure (BP) machines with oscillometric AF screening capability to use twice-daily during the cECG monitoring periods.

Main outcomes and measures: With intention-to-screen analysis, the primary outcome was AF detected by cECG monitoring or clinically within 6 months. Secondary outcomes included anticoagulant use, device adherence, and AF detection by BP monitors.

Results: Of the 856 participants, 487 were women (56.9%); mean (SD) age was 80.0 (4.0) years. Median cECG wear time was 27.4 of 28 days (interquartile range [IQR], 18.4-28.0 days). In the primary analysis, AF was detected in 23 of 434 participants (5.3%) in the screening group vs 2 of 422 (0.5%) in the control group (relative risk, 11.2; 95% CI, 2.7-47.1; P = .001; absolute difference, 4.8%; 95% CI, 2.6%-7.0%; P < .001; number needed to screen, 21). Of those with cECG-detected AF, median total time spent in AF was 6.3 hours (IQR, 4.2-14.0 hours; range 1.3 hours-28 days), and median duration of the longest AF episode was 5.7 hours (IQR, 2.9-12.9 hours). Anticoagulation was initiated in 15 of 20 patients (75.0%) with cECG-detected AF. By 6 months, anticoagulant therapy had been prescribed for 18 of 434 participants (4.1%) in the screening group vs 4 of 422 (0.9%) in the control group (relative risk, 4.4; 95% CI, 1.5-12.8; P = .007; absolute difference, 3.2%; 95% CI, 1.1%-5.3%; P = .003). Twice-daily AF screening using the home BP monitor had a sensitivity of 35.0% (95% CI, 15.4%-59.2%), specificity of 81.0% (95% CI, 76.7%-84.8%), positive predictive value of 8.9% (95% CI, 4.9%-15.5%), and negative predictive value of 95.9% (95% CI, 94.5%-97.0%). Adverse skin reactions requiring premature discontinuation of cECG monitoring occurred in 5 of 434 participants (1.2%).

Conclusions and relevance: In this randomized clinical trial, among older community-dwelling individuals with hypertension, AF screening with a wearable cECG monitor was well tolerated, increased AF detection 10-fold, and prompted initiation of anticoagulant therapy in most cases. Compared with continuous ECG, intermittent oscillometric screening with a BP monitor was an inferior strategy for detecting paroxysmal AF. Large trials with hard clinical outcomes are now needed to evaluate the potential benefits and harms of AF screening.

Trial registration: ClinicalTrials.gov Identifier: NCT02392754.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Gladstone reported receiving an operating grant from the Canadian Stroke Prevention Intervention Network (C-SPIN) for the SCREEN-AF trial (C-SPIN is a peer-reviewed national network grant funded by the Canadian Institutes of Health Research [CIHR]) during the conduct of the study; a Heart and Stroke Foundation of Canada Mid-Career Investigator Award, grants from Ontario Genomics peer-reviewed operating grant, and grants from CIHR-funded C-SPIN Network operating grant for the Ontario Holter/Echo Database Study outside the submitted work; in addition, he is chair of the Secondary Stroke Prevention Guidelines Committee for the Canadian Stroke Best Practice Recommendations (uncompensated); member of the Canadian Cardiovascular Society Atrial Fibrillation Guidelines Committee (uncompensated); he served as a site principal investigator for the NAVIGATE ESUS and NASPAF-ICH trials (all site fees paid to his institution); and he is a Canadian national coleader of the National Institute of Neurological Disorders and Stroke–sponsored ARCADIA trial. He previously served as an independent medical safety monitor for ARCADIA (uncompensated). Dr Gladstone had no personal financial relationships with pharmaceutical companies or cardiac monitoring device manufacturers in the past more than 4 years. Dr Wachter reported receiving grants from Deutsches Zentrum für Herz-/Kreislaufforschung during the conduct of the study, Deutsche Forschungsgemeinschaft, European Union, Bundesministerium für Bildung und Forschung, and Boehringer Ingelheim; personal fees from Bayer, Boehringer Ingelheim, CVRx, Daiichi, BMS, Medtronic, Novartis, Pfizer, Pharmacosmos, and Servier outside the submitted work. Dr Schmalstieg-Bahr reported receiving grants from German Centre for Cardiovascular Research (DZHK), which financed her position within the research team during the conduct of the study. Dr Quinn reported receiving personal fees from BMS-Pfizer and grants from Bayer outside the submitted work. Dr Hummers reported receiving peer-reviewed grants from the German Centre for Cardiovascular Research and Canadian Stroke Prevention Intervention Network, and nonfinancial support from iRhythm technologies during the conduct of the study. Dr Suerbaum reported the German Centre of Cardiovascular Research Scholarship allowed her to participate in the project. Dr McIntyre reported speaking fees from Servier and Bayer outside the submitted work. Dr Healey reported receiving grants from Boehringer-Ingelheim C-SPIN network during the conduct of the study; grants from BMS/Pfizer, Bayer, Medtronic, and Abbott outside the submitted work; and personal fees from Servier. No other disclosures were reported.

Figures

Figure 1.. Flow Diagram

ECG indicates electrocardiograhic.

Figure 2.. Duration of Longest Episode of Atrial Fibrillation (AF) Detected by Continuous Electrocardiographic Monitoring

Figure 3.. Time Course of Atrial Fibrillation (AF) Detection by Continuous Electrocardiographic (cECG) Monitoring in the Screening Group

The bars show when AF was first detected for each of the 20 patients with cECG-detected AF during the first (A) and second (B) monitoring periods. The curve shows the cumulative incidence of AF. Of the 20 AF cases, 8 (40%) were detected within the first week of cECG monitoring, 15 (75%) were detected within 2 weeks, 17 (85%) were detected within 3 weeks, and 3 (15%) were first detected only during the fourth week; 18 (90%) of AF cases were first detected after the first 24 hours of monitoring.