Is there a role for estrogen in the prevention and treatment of urinary incontinence?

Design: This study included 23 296 healthy, postmenopausal women aged 50–79 years enrolled in the Women’s Health Initiative hormone replacement therapy (HRT) trial and for whom baseline and 1-year data on urinary incontinence (defined as self-reported involuntary urine leakage of any amount in the past year) were available. Women were randomly assigned to receive either placebo or HRT in the form of conjugated equine estrogen (0.625 mg/d) with or without medroxyprogesterone (2.5 mg/d) based on their hysterectomy status. Participants, clinic staff and outcome assessors were blinded to group allocation. Primary outcomes were incident urinary incontinence at 1 year among women without baseline incontinence (N = 8255) and severity of incontinence among those with urinary incontinence at baseline (N = 15 041). Urinary incontinence was further subdivided by type (stress, urge or mixed). Measurements of severity included self-reported frequency, amount, associated limitations in daily activities and “degree of bother.”