Women’s Health Initiative Strong and Healthy Silent Atrial Fibrillation Recording Study: Rationale, Study Design and Baseline Data

RATIONALE: Atrial fibrillation (AF) has roughly tripled in prevalence over the last 50 years. This disease disproportionately affects morbidity and mortality among older women. Increased physical activity has been associated with lower incidence of new AF in some studies, but higher incidence in others, especially among elite athletes. PRIMARY HYPOTHESIS: We designed a randomized trial within the Women's Health Initiative (WHI) Strong and Healthy (WHISH) trial to test the hypothesis that a pragmatic intervention consisting of multimodal messaging recommending physical activity levels consistent with national guidelines would decrease the incidence of AF among a cohort of older women. DESIGN: The present WHISH Silent Atrial Fibrillation Recording (WHISH STAR) trial randomized 29,758 postmenopausal women without baseline AF who were enrolled in Medicare Fee-for-Service to the aforementioned intervention or comparison group, with planned 7-year follow-up to assess the primary outcome of incident clinical AF, namely those identified in Medicare claims. We also designed a sub-study of 1,257 women at high risk for AF (with a CHARGE-AF score ≥ 5%) to undergo serial, 7-day ECG patch monitoring to detect screened AF. We will use Cox proportional hazards models to compare the incidence of clinical AF in the participants assigned to physical activity intervention and the participants assigned to usual care groups. We will also compare the incidence of screened AF in the intervention and comparison groups detected on patch ECG monitors in the sub-study of women who underwent serial ECG patch monitoring. The WHISH STAR trial will rigorously evaluate of the effect of a pragmatic physical activity intervention on the development of AF in a large, diverse, well-characterized cohort of older women. SITES: The WHISH trial is embedded within the nationwide WHI study, enrolling postmenopausal women from 40 US clinical centers. ENROLLMENT DATES: Participants were enrolled in 2015 per the parent WHISH trial. CURRENT STATUS: WHISH STAR is in the analysis phase. TRIAL REGISTRATION: WHISH STAR has been registered on www. CLINICALTRIALS: gov (NCT05366803).