The effect of midurethral slings on persistence of urgency and urgency urinary incontinence in women with mixed urinary symptoms.

Abstract

Hypothesis / aims of study Mixed urinary incontinence (MUI) is common, with an estimated prevalence of 30% of all women with urinary incontinence, and is more bothersome than pure stress urinary incontinence (SUI) (1). Although midurethral sling (MUS) procedures are generally very effective in treating SUI, there is a concern these procedures might aggravate the urgency component and consequently patient dissatisfaction. We aim to determine the independent risk factors for persistence of urgency (pU) or persistence of urgency urinary incontinence (pUUI) following MUS procedures. Study design, materials and methods We prospectively assessed 754 consecutive women who presented with MUI, all of whom underwent MUS surgery from May 1999 till Aug 2007, with a mean follow up of 50 months. Consent was obtained from women together with approval from the local ethics committee. Comprehensive history comprised of demographics, medical history, symptoms of lower urinary tract and pelvic floor dysfunction, followed by full physical examination, urodynamics and surgical reports, recorded on a detailed proforma. pU or pUUI is defined as occurring in those women who presented initially with SUI and urinary urgency OR urgency urinary incontinence AND continue to have urinary urgency or urgency urinary incontinence, respectively at long term follow up. Women who defaulted from follow up were interviewed via telephone using structured questionnaires derived from Urogenital Distress Inventory (2). Clinical data were separated according to presence or absence of (i)pU (n=754); (ii)pUUI (n=514). Chisquare tests, independent t tests, and ANOVA tests were used to compare the two groups (presence vs. absence of pU or pUUI) by baseline characteristics and clinical factors. Clinical parameters possibly associated with each of above factors were assessed using multiple logistic regression analysis with stepwise building of an optimal model for prediction. Receiver operator curve (ROC) was performed for calculated probabilities from the final model. Results The mean age was 60.6+/-12.8 years. The overall subjective rate for pU & pUUI was 40.3% & 32.30% respectively. The mean follow-up was 218.1+/-105.3 weeks. Results of univariate analysis of clinical parameters are summarised in Table 1, with Table 2 summarising the independent risk factors for developing pU or pUUI. Length of follow up, menopausal status, use of HRT, parity, cystometric capacity, volume at first sensation, urodynamic intrinsic sphincter deficiency, level of surgical experience, type of anaesthesia, presence of intraoperative bladder perforation, use of mesh for prolapse surgery, were not significant risk factors (p>0.05). Multivariate analysis showed that urodynamic detrusor overactivity (DO), and baseline bothersome urgency confers significant odds towards pU and pUUI post MUS. Previous SUI surgery, diabetes and presence of apical prolapse confer significant odds towards pUUI. Transobturator sling, concomitant prolapse surgery and apical prolapse surgery confers inverse odds towards developing pU and pUUI respectively, following MUS. Interpretation of results Presence of urodynamic DO, bothersome urgency, previous SUI surgery, history of diabetes and presence of apical prolapse significantly increase the risks of women having pU or pUUI post MUS. Use of transobturator (TO) sling and concomitant prolapse surgery protects against pU or pUUI following MUS. The ROC for pU and pUUI indicate the model is a good fit with area under curve of 0.6782 and 0.6960 respectively. Concluding message Urodynamic DO, bothersome urgency, previous SUI surgery, history of diabetes and apical prolapse significantly increases, whereas TO sling and concomitant prolapse surgery decreases the risk of women having persisting overactive bladder symptoms following MUS. (Table presented). (Graph presented).