HRT increases risk of stress and urge urinary incontinence

Question Can hormone replacement therapy (HRT) decrease the risk of urinary incontinence in postmenopausal women?

Synopsis As predicted, more spin-off studies are coming from the women's health initiative multicenter clinical trial of hormone therapy in postmenopausal women. These investigators randomised 27 347 postmenopausal women aged 50-79 to active treatment (oestrogen alone or oestrogen plus progestin) or placebo. The randomisation (concealed allocation assignment) was based on hysterectomy status. Outcomes were assessed by individuals blinded to treatment group assignment. Follow-up was available at one year for 96% of the women. With intention to treat analysis, hormone replacement therapy with oestrogen alone or oestrogen plus progestin increased the risk for urge urinary incontinence (14% v 13%; number needed to harm (NNH) = 100) and stress urinary incontinence (17% v 9%; NNH = 13; 95% CI 10 to 15) compared with placebo.

Bottom line Despite what we learnt about the beneficial effects of hormone replacement therapy on reversing urethral and bladder mucosal atrophy, postmenopausal women using either oestrogen alone or oestrogen plus progestin are at an increased risk of both stress and urge urinary incontinence.

Level of evidence 1b (see www.infopoems.com/levels.html). Individual randomised controlled trials (with narrow confidence interval).