While the management of bladder outlet obstruction (BOO) in men has been a topic of several systematic reviews and meta-analysis, no such evidence base exists for female BOO. The aim of this systematic review was to evaluate the benefits and harms of therapeutic interventions for the management of bladder outlet obstruction in women.

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement and the principles outlined in the Cochrane Handbook for Systematic Reviews. The study protocol was registered with PROSPERO (CRD42020183839). A systematic literature search using the Medline, Embase and CENTRAL as well as clinicaltrial.gov was performed and updated by a research librarian in May 2020. The study population consisted of adult female patients (≥18 years) diagnosed with BOO. The therapeutic interventions considered for inclusion were conservative treatments (e.g. physiotherapy, and vaginal pessary) pharmacological treatments (e.g. alpha-blockers) or surgical interventions (e.g. sacral neuromodulation, urethroplasty, etc).

Out of 6344 records, we identified 30 studies enrolling 963 participants, of which only five RCTs were found including a total of 417 participants. One prospective non-randomized comparative study and three retrospective comparative studies were also identified, and all the other included studies were prospective non-comparative case series. Most of the studies were of unclear or low methodological quality. One placebo-controlled cross-over randomized trial assessed the role of baclofen in 60 female patients with dysfunctional voiding. The trial met its primary endpoint with a significantly greater decrease in the number of voids/day in the baclofen group (-5.53 vs. -2.70; p=0.001). The adverse events were mild and comparable in both groups (25% vs. 20%). One placebo-controlled cross-over randomized trial assessed the role of sildenafil in 20 women with Fowler’s syndrome. There were significant improvements from baseline in Qmax, IPSS, and post-void residual (PVR) but with no statistically significant difference when compared with placebo. In a large RCT including 197 female patients with functional BOO, the alpha adrenoreceptor antagonist, alfusozin significantly improved IPSS, Qmax and PVR compared to baseline but the differences compared to the placebo group were not statistically significant. Several small single arm prospective series reported improvement of BOO related symptoms and voiding parameters with urethroplasty, sling revision, urethral dilation, vaginal pessary and pelvic organ prolapse repair.

The present systematic review is, to our knowledge, the first aiming to evaluate the evidence supporting all existing treatments for female BOO. We found that the vast majority of the therapeutic options currently used to treat female BOO is supported by scant and poor evidence.

Evidence to support the use of conservative, pharmacological and surgical treatments for either anatomical or functional BOO are scarce. Baclofen is the only treatment that demonstrated superior efficacy compared to placebo in female patients with functional BOO. Alpha-blockers and sildenafil improve voiding parameters in female with functional BOO but did not show superior efficacy when compared to placebo.  Urethroplasty, transurethral bladder neck incision, midurethral sling revision and urethral dilation are only supported by small sample single arm prospective series