Screening for Atrial Fibrillation in Older Adults at Primary Care Visits: the VITAL-AF Randomized Controlled Trial

Background: Undiagnosed atrial fibrillation (AF) may cause preventable strokes. Guidelines differ regarding AF screening recommendations. We tested whether point-of-care screening with a handheld single lead electrocardiogram (ECG) at primary care practice visits increases diagnoses of AF. Methods: We randomized 16 primary care clinics 1:1 to AF screening using a handheld single-lead ECG (AliveCor KardiaMobile) during vital sign assessments, or usual care. Patients included were aged ≥65 years. Screening results were provided to primary care clinicians at the encounter. All confirmatory diagnostic testing and treatment decisions were made by the primary care clinician. New AF diagnoses over one-year follow-up were ascertained electronically and manually adjudicated. Proportions and incidence rates were calculated. Effect heterogeneity was assessed. Results: Of 30,715 patients without prevalent AF (n=15,393 screening [91% screened], n=15,322 control), 1.72% of individuals in the screening group had new AF diagnosed at one year versus 1.59% in the control group (risk difference [RD] 0.13%, 95% confidence interval [CI] -0.16-0.42, P=0.38). In prespecified subgroup analyses, new AF diagnoses in the screening and control groups were greater among those aged ≥85 years (5.56% versus 3.76%, respectively, RD 1.80%, 95% CI 0.18-3.30). The difference in newly diagnosed AF between the screening period and the prior year was marginally greater in the screening versus control group (0.32% versus -0.12%, RD 0.43%, 95% CI -0.01-0.84). The proportion of individuals with newly diagnosed AF who were initiated on oral anticoagulants was not different in the screening (n=194, 73.5%) and control (n=172, 70.8%) arms (RD 2.7%, 95% CI -5.5-10.4). Conclusions: Screening for AF using a single-lead ECG at primary care visits did not affect new AF diagnoses among all individuals aged 65 years or older compared to usual care.