#423 Estrogen – an answer to a burning question?
CLINICAL QUESTION
Does estrogen reduce urinary tract infections (UTIs) in post-menopausal women?
BOTTOM LINE
In women with recurrent UTIs or urogenital symptoms, vaginal estrogens reduce the number of women with UTIs from 24% to 10% at ~1 year. Women with recurrent UTIs may see the largest benefit. Oral estrogens are not effective.
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EVIDENCE
- Results statistically significant unless stated.
- One systematic review, 8 Randomized Controlled Trials (RCTs), postmenopausal women with either urogenital symptoms or recurrent UTIs.1
- Proportion of women with any UTI, all patients:
- Oral estrogen (3 RCTs, 2766 patients). At 12 weeks–4 years: Not statistically different.
- Vaginal estrogen (cream, ovule, ring) (5 RCTs, 1936 patients). At 32-52 weeks: 9.9% versus 24% (placebo), Number Needed to Treat (NNT)=8.
- In largest RCT in above review,2 women had urogenital symptoms, 341/1612 had ≥1 UTI in past year. 25mcg vaginal estradiol tablet or placebo. At 12 months:
- All women with any UTI: 6.2% versus 16% (placebo).
- RCTs in women with ≥2 UTIs in past 6-18 months, proportion with UTI:
- Vaginal estradiol ring (2mg) versus no treatment (1 RCT, 108 patients). At 9 months:3
- 51% versus 80% (no treatment), NNT=4.
- Estriol cream 0.5mg with applicator versus placebo cream (1 RCT, 93 patients). At 8 months:4
- 16% versus 63% (placebo), NNT=3.
- Vaginal estradiol ring (2mg) or conjugated estrogen cream (0.625 mg/g) dosed at 0.5g twice a week versus placebo cream (1 RCT, 35 patients). At 6 months:5
- 61% (ring/cream) versus 94% (placebo cream), NNT=4.
- Vaginal estradiol ring (2mg) versus no treatment (1 RCT, 108 patients). At 9 months:3
- Proportion of women with any UTI, all patients:
- Adverse events:1 No difference.
- Limitations:1 Primarily small studies, high drop-out rates.
CONTEXT
- Guidelines recommend vaginal estrogen therapy for recurrent, uncomplicated UTIs in peri- and post-menopausal women.6
- Topical estrogens reduce the percentage of women with incontinence episodes (baseline ~30% reduced to 14% estrogen versus 18% placebo).2 Oral estrogens have no effect and may possibly worsen symptoms.7
- Daily antibiotics for 6-12 months: 1 UTI: 7% (antibiotics) versus 51% (placebo).
- 15% will experience an adverse event versus 8% with placebo.8
- Based on 1 high-quality RCT, increasing daily water intake by 1.5L per day (in women with low baseline intake) resulted in 1.5 fewer UTIs/year.9
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