REACT AF
REACT‑AF is a multicenter, randomized (1:1), open‑label, blinded endpoint (PROBE) phase III trial testing whether a smartwatch‑guided strategy of short, on‑demand direct oral anticoagulant (DOAC) therapy can prevent stroke and death while reducing bleeding compared with standard continuous DOAC therapy. The trial will enroll about 5,350 adults aged 22-85 with paroxysmal or persistent (non‑permanent) atrial fibrillation and a CHA2DS2‑VASc score of 1-4 (men) or 2-4 (women) without prior stroke or TIA, who are already taking a DOAC at screening.
Participants are randomized to one of two arms: 1) experimental - an AF‑sensing smartwatch that, when it detects a qualifying AF episode (>1 hour), triggers a prescribed 30‑day course of a DOAC; or 2) control - continued standard daily DOAC therapy. Remote continuous smartwatch monitoring is used for detection and follow‑up. Follow‑up lasts up to 60 months with regular clinic and remote visits per site protocol.
The primary objective is to demonstrate non‑inferiority of the smartwatch‑triggered, time‑limited DOAC strategy versus continuous DOAC for a composite primary outcome of ischemic stroke, systemic embolism, and all‑cause mortality. A key secondary objective is to test whether the smartwatch‑triggered strategy is superior in reducing major bleeding events. Additional safety and exploratory endpoints include AF burden, hospitalization, and adherence measures. Patients with valvular/permanent AF, prior stroke/TIA, very high AF burden, need for other permanent anticoagulation indications, severe renal disease, recent AF procedures, implanted rhythm devices affecting management, pregnancy, or other conditions increasing bleeding risk are excluded.