Effects of Postmenopausal Hormone Therapy on incident Atrial Fibrillation: The Women’s Health Initiative Randomized Controlled Trials
Clinical Trials Saturday, December 1st, 2012AHA: 11/20/12
Background—Atrial fibrillation (AF) is less prevalent in women versus men, but associated with higher risks of stroke and death in women. The role hormone therapy plays in AF is not well understood.
Methods and Results—The Women’s Health Initiative (WHI) randomized postmenopausal women to placebo or conjugated equine estrogens (CEE; 0.625 mg/d) plus medroxyprogesterone acetate (MPA; 2.5 mg/d) if they had a uterus (N=16,608) or to CEE only if they had prior hysterectomy (N=10,739). Incident AF was identified by electrocardiograms and diagnosis codes from Medicare claims or hospitalization records. Hazard ratios for incident AF were estimated using Cox proportional hazards regression. After excluding participants with baseline AF, there were 611 incident AF cases over a mean of 5.6 years among 16,128 E+P participants, and 683 cases over a mean of 7.1 years among 10,251 CEE alone participants. Incident AF was more frequent in the active groups of both trials, reaching statistical significance in the trial of CEE alone in women with prior hysterectomy (HR 1.17, CI 1.00-1.36, P=0.045) and in the pooled analysis (HR 1.12, CI 1.00-1.24, p=0.05), but not in the E+P trial (HR 1.07, CI 0.91-1.25, p=0.44). These results were only minimally affected by adjustment for incident stroke, coronary heart disease, and heart failure. Read more
