Randomized Invitation to Systematic NT-proBNP and ECG Screening in 75-Year Olds to Detect Atrial Fibrillation -STROKESTOP II

Background: Guidelines have suggested screening for atrial fibrillation to enable early treatment and avoid downstream negative clinical events. We aimed to determine if atrial fibrillation screening potentially enhanced by NT-proBNP would reduce stroke or systemic embolism incidence as compared to in a control group and to determine if it was safe for those with low NT-proBNP concentrations to forfeit prolonged screening. Methods: In this randomized controlled trial all 75/76-year-old individuals in Stockholm Region, Sweden were randomized 1:1 to be invited to screening or serve as a control group. NT-proBNP concentration were measured and a single-lead-ECG registered only once if NT-proBNP<125ng/L, whereas if NT-proBNP≥125 ng/L participants underwent prolonged screening, recording single-lead ECGs four times daily for two weeks. If atrial fibrillation was detected, treatment was initiated. Baseline and outcome data were collected from Swedish National Registries. Results: In total 28,712 individuals were randomized, after exclusion of death and emigration 13,905 remained in the intervention group, 13,884 in the control group. Participation rate in the intervention group was 49.2% (6,843/13,905). Participants in the high NT-proBNP group (NT-proBNP≥125 ng/L) without prior atrial fibrillation constituted 60% of the total and underwent prolonged screening. New AF was detected in 2.4% (165/6,843) in the intervention group. There was no difference in AF prevalence or oral anticoagulant treatment between the intervention and the control group after five years follow-up. After a median of 5.1 years (IQR 5.0-5.8) there was no difference in the primary outcome of stroke or systemic embolism between the intervention group and the control group, HR: 0.96 (95% CI 0.86-1.06). The low NT-proBNP-group had significantly fewer strokes or systemic emboli than the control group, HR: 0.59 (95% CI 0.46-0.74), p<0.001. In the high NT-proBNP group the risk of stroke or systemic embolism was higher compared to the low NT-proBNP group, HR: 1.57 (95% CI 1.22-2.02), p=0.001. Conclusions: In this population-based screening trial for atrial fibrillation using NT-proBNP for screening enhancement, there was no difference in risk of stroke or systemic embolism for the intervention group compared to controls. Participation was moderate. The use of NT-proBNP for screening enhancement was safe in identifying low-risk participants. Clinical Trial Registration: www.clinicaltrials.gov; NCT02743416