The SAFER study (Screening for Atrial Fibrillation with ECG to Reduce stroke): is it feasible to screen for paroxysmal atrial fibrillation in general practice?
Problem
Atrial Fibrillation (AF) is a major risk factor for ischaemic stroke unless treated with an anticoagulant. Detecting AF can be difficult because it is often paroxysmal and asymptomatic. Many clinicians support AF screening. The UK National Screening Committee and the US Preventive Services Task Force have highlighted a lack of evidence that screening for AF is beneficial. Informing a large (n=126,000) cluster randomised controlled trial in UK general practice, this feasibility study aimed to quantify: participation rates, screening uptake, AF detection rate, and anticoagulation uptake.
Approach
8,000 people aged ≥65 registered with a participating practice (n=10) were invited to the study. Those that consented to take part were invited to a practice AF screening appointment, and instructed how to use a handheld single-lead ECG device (Zenicor). They continued screening at home (1-4 weeks). ECGs were reviewed by a computer algorithm, a technician and (if potentially ‘positive’) a cardiologist. Treatment for AF followed national guidelines.
Findings
Results from practices 1-5 (full results will be presented):1,644/4,000 (41%) of people consented to take part in the study. 1,375/1,512 (91%) of people invited for screening accepted. To date, AF was detected in 3.1% (4-week screen, 31/987), and in 0.9% (1-week screen, 3/347). 17 people with ‘positive’ results are still under review, and 19 had indeterminate results. Anticoagulation commenced in 27/34 (79%) people.
Consequences
It is feasible to screen for AF in general practice. We will modify the screening process in the trial; raising the lower age limit to 70 years and screening for three weeks per participant.