Predictors of occult stress urinary incontinence

Background: Causes for occult stress urinary incontinence (SUI) are poorly recognised.

Aims: To explore the mechanisms behind occult SUI. We hypothesised that cystocele type affects the risk of occult SUI.

Materials and methods: We conducted a retrospective, cross-sectional study on 878 consecutive women assessed at a tertiary urogynaecologic clinic between July 2016 and November 2018. The population of this study consisted of 424 women with urodynamic stress incontinence. Women with previous anti-incontinence surgery were excluded. All women underwent a standardised interview, clinical examination and urodynamic testing. Translabial ultrasound was used to categorise cystoceles into Green type II (cystocele with open retrovesical angle) and Green type III (cystocele with intact retrovesical angle). We compared women with overt SUI to those with occult SUI (defined as stress incontinence only observed after prolapse reduction) for demographic characteristics, urodynamic findings and functional anatomy. Predictors for occult SUI were identified with a multivariable logistic regression model.

Results: Of 424 women, 362 (85%) had overt, and 62 (15%) occult SUI. There were 136 (32%) women who had a significant cystocele on imaging; 57 (42%) were classified as type II and 79 (58%) as type III. On multivariable regression, age and cystocele type were significantly associated with occult SUI. Odds for occult SUI was 10.9 times higher with type III (cystocele with an intact retrovesical angle) than with type II cystocele (cystocele with an open retrovesical angle; 95% CI 1.3-90.9).

Conclusions: Cystocele type affects the risk of occult SUI. Type III cystocele (intact retrovesical angle) associates with occult SUI.