Oestrogens for urinary incontinence in women

It is possible that oestrogen deficiency may be an aetiological factor in the development of urinary incontinence in women.

To assess the effects of oestrogens used for the treatment of urinary incontinence.

We searched the Cochrane Incontinence Group trials register (November 2002) and the reference lists of relevant articles. Date of the most recent searches: November 2002.

Randomised or quasi-randomised controlled trials that included oestrogens in at least one arm, in women with symptomatic or urodynamic diagnoses of stress, urge or mixed incontinence or other urinary symptoms.

Trials were evaluated for methodological quality and appropriateness for inclusion by the reviewers. Data were extracted by all three reviewers and cross checked. Trial results were analysed within clinical subgroups or by intervention. Where appropriate, meta-analysis was undertaken.

Twenty eight trials were identified which included 2926 women. Sample sizes ranged from 16 to 1525. The trials used varying combinations of type of oestrogen, dose, duration of treatment and length of follow up. Outcome data were not reported consistently and were available for only a minority of trials. In the 15 trials that compared oestrogen with placebo, 374 women received oestrogen and 344 placebo. Subjective impression of cure was higher amongst those treated with oestrogen for all categories of incontinence (36/101, 36% versus 20/96, 21%; RR for cure 1.61, 95% CI: 1.04 to 2.49). When subjective cure and improvement were considered together, a statistically higher cure and improvement rate was shown for both urge (35/61, 57% versus 16/58, 28% on placebo) and stress (46/107, 43% versus 29/109, 27%) incontinence. For women with urge incontinence, the chance of cure or improvement was approximately a quarter higher again than in women with stress incontinence. Taking all trials together, the data suggested that about 50% of women treated with oestrogen were cured or improved compared with about 25% on placebo. Overall, there were around 1 to 2 fewer voids in 24 hours amongst women treated with oestrogen. The effect again appeared to be larger amongst women with urge incontinence. There were no statistically significant differences in respect of frequency, nocturia or urgency. No serious adverse events were reported although some women experienced vaginal spotting, breast tenderness or nausea. In a large trial conducted amongst women with heart disease, data from a subset who had incontinence suggested that women treated with a combination of oestrogen and a progestogen had lower subjective cure or improvement rates compared to the placebo group (RR 0.85, 95% CI 0.76 to 0.95). The data were too few to address other questions about oestrogens compared with, or in combination with, other treatments, different types of oestrogen or different modes of delivery.

Oestrogen treatment can improve or cure incontinence and the evidence suggests that this is more likely with urge incontinence. There was little evidence from the trials after oestrogen treatment had finished and none about long-term effects. Combined oestrogen and progesterone appeared to reduce the likelihood of cure or improvement. There were too few data to address reliably other aspects of oestrogen therapy such as oestrogen type, dose and route of administration. However, the risk of endometrial and breast cancer after long-term use suggests that oestrogen treatment should be for limited periods, especially in women with an intact uterus.