A systematic review of the effects of estrogens for symptoms suggestive of overactive bladder

Objective. To perform a systematic review of the effects of estrogen therapy on symptoms suggestive of overactive bladder (OAB) in postmenopausal women. Materials and methods. This analysis involved a literature review of Medline, Excerpta Medica, and the Science Citation Index and a manual search of popular urology, gynecology, gerontology, and primary care medicine journals from January 1969 to December 1999. Articles had to include estrogen and placebo treatment groups, published or original data presented at a scientific meeting and report symptoms suggestive of OAB. This search identified 11 randomized trials and included a total of 430 subjects. Thirty-six subjects who participated in two crossover studies received both estrogen and placebo and thus are counted twice, therefore 236 received estrogen therapy and 230 were placebo controls. Estrogen was administered systemically or locally as estriol, estradiol, conjugated estrogen, or estradiol and estriol. A meta-analysis of these studies was performed for all estrogen therapies and then separately for systemic and local therapies. Results. Overall, estrogen therapies were associated with statistically significant improvements in all outcome variables: diurnal frequency (P = 0.0011), nocturnal frequency (P = 0.0371), urgency (P = 0.0425), number of incontinence episodes (P = 0.0002), first sensation to void (P = 0.0001), and bladder capacity (P = 0.0018). Local therapies had statistically significant beneficial effects on all outcome variables. However, systemic therapies were only associated with significant improvements in incontinence episodes and first sensation to void while nocturnal frequency actually worsened. Conclusion. Estrogen therapy may be effective in alleviating the symptoms suggestive of OAB. Local administration may be the most beneficial route of administration.