Effect of intrinsic sphincter deficiency on midurethral sling outcomes in women with mixed urinary incontinence.

Objective The objective of this study was to estimate the effect of intrinsic sphincter deficiency (ISD) on frequency and urge incontinence after midurethral sling (MUS) in women with mixed urinary incontinence (MUI). Methods We performed a retrospective study of 137 women with MUI who underwent MUS placement. We defined MUI as an affirmative response to the urge incontinence item (no. 16) on the Pelvic Floor Distress Inventory in a cohort of women with urodynamic stress incontinence. Intrinsic sphincter deficiency was defined as preoperative positive leak point pressure of less than 60 cm H2O and/or urethral closure pressure less than 20 cm H2O. Outcomes included resolution of frequency and urge incontinence as well as resolution of stress incontinence. Multivariable logistic regression was performed to estimate the association between ISD and urinary outcomes. Results One hundred thirty-seven women met our study inclusion criteria. Fifteen (11%) had preoperative ISD, and 122 (89%) did not. At 6 to 12 months after MUS placement, 67% of women with ISD-MUI versus 39% with non–ISD-MUI had complete resolution of both urinary frequency and urge incontinence (P = 0.04). The 2 groups did not differ postoperatively in regard to complete resolution of stress incontinence symptoms (85% vs 90%, P = 0.63). On regression analysis, women with ISD-MUI had increased odds of complete resolution of frequency and urge incontinence compared with women with non–ISD-MUI (adjusted odds ratio, 5.38 [95% confidence interval, 1.50–19.3]). Conclusions In women with MUI, preoperative ISD is associated with increased odds of urinary frequency and urge incontinence resolution after MUS.