Persistence of urgency and urge urinary incontinence in women with mixed urinary symptoms after midurethral slings: a multivariate analysis

Authors


  • This study was presented at the International Continence Society/International Urogynecological Association in Toronto 2010.

Dr J Lee, c/o Department of Urogynaecology, Mercy Hospital for Women, 169 Studley Road, Heidelberg, Vic. 3084, Australia. Email joseph.lee@southernhealth.org.au

Abstract

Please cite this paper as: Lee J, Dwyer P, Rosamilia A, Lim Y, Polyakov A, Stav K. Persistence of urgency and urge urinary incontinence in women with mixed urinary symptoms after midurethral slings: a multivariate analysis. BJOG 2011;118:798–805.

Objective  To determine risk factors for persistence of urgency or urge urinary incontinence following midurethral sling surgery.

Design  Prospective cohort study.

Setting  Tertiary referral Urogynaecology Unit.

Sample  A total of 754 consecutive women with stress urinary incontinence (SUI) and urgency; and 514 women with SUI and urge urinary incontinence (UUI) who underwent midurethral sling with a mean follow up of 50 months.

Methods  Women with persistent urgency or UUI at long-term follow up were compared with those whose symptoms had resolved, using multivariate analysis to determine the risk factors for persistent symptoms.

Main outcomes measures  Odd ratios (OR) of independent risk factors for persistent urgency or UUI.

Results  Persistent urgency (304/754, 40%) and UUI (166/514, 32%) were common. Coexistent detrusor overactivity (OR 2.04, 95% CI 1.39–3.01), baseline symptom severity (OR 1.41, 95% CI 1.10–1.78) and age (OR 1.03, 95% CI 1.02–1.04) increased the risk of persistent urgency, while transobturator sling surgery (OR 0.61, 95% CI 0.39–094) and concomitant prolapse surgery (OR 0.54, 95% CI 0.38–0.75) decreased the risk. For UUI detrusor overactivity (OR 1.86, 95% CI 1.18–2.93), baseline symptom severity (OR 1.88, 95% CI 1.38–2.56), previous incontinence surgery (OR 2.18, 95% CI 1.28–3.70) increased the risk of persistence, whereas apical prolapse surgery (OR 0.33, 95% CI 0.15–0.70) decreased the risk. Women were more likely not to recommend surgery when they experienced persistent urgency (15.8% versus 2.7%, P < 0.0001) or UUI (24.7% versus 2.9%, P < 0.0001).

Conclusions  Urodynamic parameters, baseline urgency symptom severity, midurethral sling route and concomitant prolapse operation are important predictors of persistent urgency or UUI following midurethral sling.

Introduction

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 Population-based prevalence studies have indicated a greater impact on health-related quality of life from MUI compared with SUI.2 Not surprisingly, women who undergo surgery have a high expectation of outcome, which includes resolution of urinary urgency.3 Although surgery is a common and effective intervention for SUI, with midurethral sling procedures becoming increasingly popular,4,5 there is concern that these procedures might aggravate pre-existing urgency or urge urinary incontinence (UUI). Randomised controlled trials of retropubic versus transobturator midurethral slings have suggested that the rate of persistent overactive bladder (OAB) symptoms following midurethral slings is in the order of 11–30%.6,7

Despite the absence of a widely accepted definition of persistent urgency, logically the term implies that women have urgency symptoms preoperatively and continue to have urgency postoperatively. Significant prevalence rates of persistent OAB symptoms following midurethral slings underscore the need to identify women at risk of developing these bothersome postoperative symptoms. This could facilitate optimal preoperative counselling directed towards acceptable patient expectations. We aimed to evaluate the effect of midurethral slings on persistent OAB symptoms with a view to identifying the independent risk factors for development of persistent urgency or persistent UUI following midurethral sling procedures.

Methods

The study involved 1225 consecutive women, all of whom underwent midurethral sling surgery between May 1999 and August 2007, with a mean follow up of 50 months. This observational cohort study included both retrospective (May 1999 to January 2007) and prospective (January to August 2008) data collection. All women gave consent to undergo urogynaecological assessment and be included in the study. The local hospital ethics committee approved the project (R08/08). Comprehensive history comprised demographics, medical history, symptoms of lower urinary tract and pelvic floor dysfunction, followed by full physical examination, and urodynamic and surgical reports recorded on a detailed proforma. Methods, definitions and units conformed to the standards jointly recommended by the International Continence Society and the International Urogynecological Association, except where specifically noted.8

Intrinsic sphincter deficiency was defined as a maximum urethral closure pressure of 20 cmH2O or less9 or a pressure rise from baseline required to cause urinary incontinence (Δ Valsalva or cough leak point pressure) of 60 cmH2O or less.10

All midurethral slings were placed in the standard manner as previously described,11,12 with the selection of the sling made by individual surgeons based on their clinical preference. Routine retropubic hydrodissection using a mixture of local anaesthetic and normal saline was performed in all retropubic slings. Intraoperative cystourethroscopy was also routinely performed on all retropubic and transobturator slings.

Postoperative evaluations were scheduled at 6 weeks, 6 months, 12 months and annually thereafter. Women who defaulted from follow up were interviewed via telephone using structured questionnaires (see Supporting Information, Appendix S1) examining urinary symptoms. The questionnaire included questions from previously validated questionnaires: the Urogenital Distress Inventory13 and the Pelvic Floor Distress Inventory.14 Baseline urinary urgency was graded into no symptoms (0), occasional symptoms (1) or frequent symptoms (2). In this long-term study, the overall satisfaction of the woman with the operation was assessed by asking whether she would have the operation again or recommend it to a friend.

Persistent urgency or persistent UUI was defined as occurring in those women who presented before surgery with urgency or UUI and continued to experience urgency or UUI, respectively, following midurethral sling surgery at long-term follow up.

Analysis was performed using the statistical package stata 9.2 for Windows (StataCorp LP 2007; College Station, TX, USA). Clinical data, including surgical reports, were separated according to presence or absence of (i) persistent urgency (n = 754); (ii) persistent UUI (n = 514). Chi-square tests, independent t tests and analysis of variance tests were used to compare two groups (presence or absence of persistent urgency, persistent UUI) by baseline characteristics and clinical factors. Clinical parameters that could be associated with each of the above factors were assessed using multiple logistic regression analysis with a backward stepwise building of an optimal model for prediction. The significant levels of entering and removing an explanatory variable were set to 0.30 and 0.05, respectively. The goodness of fit of the model to the observed data in our sample was evaluated using Hosmer–Lemeshow statistics. Receiver operator curve was used for calculated probabilities from the final model.

Results

The mean age of women was 60.6 ± 12.8 years and the mean follow-up was 218.1 ± 105.3 weeks, with a minimum follow up of 12 months. Of the women, 91% (n = 1112) completed the follow up and questionnaire. The remaining women could not be contacted because of death (n = 21) or change of residence (n = 92). Sixty-two percent of the women reported symptoms of urgency (= 754) or urge urinary incontinence (n = 514) at baseline and were included in the analysis. Of the slings, 955 (78%) were retropubic slings (tension-free vaginal tape [TVT] 87%, Advantage sling 11%, suprapubic arch sling [SPARC] 2%) and 270 (22%) were transobturator slings (Monarc 91%, TVT-O 9%) (TVT®/TVT-O®, Gynecare, Somerville, NJ, USA; Advantage®, Boston Scientific, Natick, MA, USA; SPARC®/Monarc®, American Medical Systems, Minnetonka, MN, USA). There were more retropubic slings than transobturator slings because the latter were introduced later.

Tables 1 and 2 show the characteristics of women who reported SUI and urgency at baseline and subsequently developed persistent urgency after midurethral slings at long-term follow up. Their urgency persisted in 304 out of 754 (40.3%) women, with a resolution rate of preoperative urgency being 59.7%. Among 49 women who reported urgency only (no SUI) at baseline, 42 had urodynamic stress incontinence (USI) and seven had both USI and detrusor overactivity. In this group of women, there was no significant difference between the proportion of those who went on to have persistence and thos who had resolution of their urgency at long-term follow up (6.3% versus 6.7%, P = 0.820).

Table 1.   Preoperative characteristics of women with persistence of urgency or urge urinary incontinence after midurethral sling
 Preoperative urgency (n = 754)Preoperative urge urinary incontinence (n = 514)
Postoperative persistenceYes (n = 304) (40.3%)No (n = 450) (59.7%)P valueYes (n = 166) (32.3%)No (n = 348) (67.7%)P value
  1. Ant VagPOP stg > 1, anterior vaginal wall prolapse stage > 1; Apical VagPOP stg > 1, apical vaginal (or uterine) prolapse stage > 1; BMI, body mass index; CST pos., Cough stress test positive; POP, pelvic organ prolapse; Post VagPOP stg > 1, posterior vaginal prolapse stage > 1. *Baseline degree of bothersome urgency: 0 = nil, 1 = occasional, 2 = daily.

Age (years) mean ± SD 63.6 ± 12.3 58.7 ± 13.0<0.0001 63.6 ± 11.9 60.5 ± 12.70.472
Follow up (weeks) mean ± SD 209.3 ± 102 222.8 ± 1080.079 228.2 ± 110 218.9 ± 1050.504
Parity mean ± SD 2.81 ± 1.582 2.76 ± 1.3710.638 2.41 ± 1.152 2.54 ± 1.5990.461
Lower urinary tract symptoms at baseline
SUI and urgency/UUI285 (93.8)420 (93.3) 154 (92.7)333 (95.7) 
Urgency/UUI only19 (6.3)30 (6.7)0.82012 (7.2)15 (4.3)0.165
Bothersome urgency*227 (74.7)274 (60.9)<0.0001134 (86.5)219 (65.6)<0.0001
D. Frequency: <679 (26.0)127 (28.2) 34 (20.5)101 (29.0) 
D. Frequency: 6–10153 (50.3)238 (52.9) 84 (50.6)178 (51.2) 
D. Frequency: 11–1551 (16.8)68 (15.1) 34 (20.5)51 (14.7) 
D. Frequency: >1521 (6.9)17 (3.8)0.22113 (7.8)18 (5.2)0.0919
N. Frequency: 034 (11.2)84 (18.7) 18 (10.8)56 (16.10 
N. Frequency: 1–2183 (60.2)267 (59.3) 93 (56.0)212 (60.9) 
N. Frequency: 3–468 (22.4)75 (16.7) 46 (27.7)57 (16.4) 
N. Frequency: >419 (6.3)24 (5.3)0.029 (5.4)23 (6.6)0.018
Voiding difficulty47 (15.5)56 (12.4)0.23725 (15.06)46 (13.22)0.571
Medical history
Menopausal29 (9.5)88 (19.6) 20 (12.1)50 (14.4) 
Post hysterectomy271 (89.1)351 (78.0)<0.0001144 (86.8)293 (84.2)0.069
Use of HRT37 (12.2)57 (12.7)0.8418 (10.8)49 (14.1)0.308
Previous POP surgery115 (37.8)144 (32.0)0.09864 (38.6)121 (34.8)0.403
Previous SUI surgery64 (21.1)66 (14.7)0.02343 (25.9)49 (14.1)0.001
Previous Burch Colpo.40 (13.2)46 (10.2)0.21428 (16.8)29 (8.3)0.004
Previous Sling24 (7.9)20 (4.4)0.04715 (9.0)20 (5.8)0.166
Physical examination
BMI mean ± SD 28.6 ± 4.4 27.3 ± 5.6<0.0001 26.5 ± 4.0 28.4 ± 4.80.001
BMI > 3095 (31.3)109 (24.2)0.0463 (38.0)86 (24.7)0.021
Ant VagPOP stg > 1226 (74.3)338 (75.1)0.47114 (68.7)263 (75.6)0.105
Apical VagPOP stg > 1178 (58.6)263 (58.4)0.47586 (51.8)209 (60.1)0.083
Post VagPOP stg > 1205 (67.4)318 (70.7)0.324105 (63.3)260 (74.7)0.012
CST pos.156 (51.3)242 (53.8)0.67875 (46.6)183 (52.6)0.123
Table 2.   Urodynamic and operative characteristics of women with persistence of urgency or urge urinary incontinence after midurethral sling
 Persistent urgency (n = 754)Persistent urgency urinary incontinence (n = 514)
Postoperative persistenceYes (n = 304) (40.3%)No (n = 450) (59.7%)P valueYes (n = 166) (32.3%)No (n = 348) (67.7%)P value
  1. Apical stg < 1 No OP, Apical vaginal wall (or uterine) prolapse stage <1 with no apical operation; Apical stg > 1 No OP, apical vaginal wall (or uterine) prolapse stage > 1 with no apical operation; Apical stg > 1 Apical OP, apical vaginal wall (or uterine) prolapse stage > 1 with apical operation; Apical POP/Apical Op, Apical vaginal wall (or uterine) prolapse with apical operation; Capacity, volume at maximum capacity; ISD, intrinsic sphincter deficiency, defined as MUCP < 20 cmH2O and/or Δ valsalva leak point or cough leak point pressure <60 cmH2O; Less experienced surgeon, Fellows, Registrars, residents, typically performed <50;

  2. MUCP, maximum urethral closure pressure; MUS, midurethral sling procedure; OSI, Occult stress incontinence; stress incontinence observed (only) after reduction of co-existent prolapse;

  3. POP, pelvic organ prolapse; Q<15 and/or PVR > 50, maximum flow rate <15 m/seconds and/or post-void residual > 50 ml; USI and DO, urodynamic stress incontinence and detrusor overactivity; 1st Sens, volume at first sensation.

Urodynamic parameters
Capacity (ml) mean ± SD 459.2 ± 94.5 456.2 ± 76.20.462 454.2 ± 92.1 458.0 ± 80.60.455
1st Sens (ml) mean ± SD 239 ± 101.7 241 ± 107.50.743 237 ± 108.4 247 ± 109.80.653
MUCP empty (cmH2O) mean ± SD 37.85 ± 18.11 40.2 ± 18.570.087 37.41 ± 19.3 40.9 ± 19.10.682
MUCP full (cmH2O) mean ± SD 32.95 ± 18.05 35.5 ± 17.630.063 31.99 ± 19.5 35.9 ± 18.80.169
No leakage5 (1.6)13 (2.9) 1 (0.6)13 (3.7) 
OSI15 (4.9)27 (6.0) 8 (4.8)14 (4.0) 
USI194 (63.8)347 (77.1) 99 (59.6)250 (71.8) 
DOI only2 (0.7)3 (0.7) 2 (1.2)2 (0.6) 
USI and DO88 (29.0)60 (13.3)<0.000156 (33.7)69 (19.8)0.003
ISD44 (14.5)67 (14.9)0.87527 (16.3)48 (13.8)0.458
Q<15 and/or PVR > 5046 (15.1)45 (10.0)0.03728 (16.9)45 (12.9)0.254
Surgical operation
Less experienced surgeon107 (35.2)165 (36.7)0.6861 (36.8)119 (34.2)0.571
General anaesthesia123 (40.5)90 (34.8) 65 (39.2)122 (35.1) 
Regional anaesthesia52 (17.1)50 (19.3) 32 (19.3)62 (17.8) 
Local anaesthesia129 (42.3)119 (46.0)0.2469 (41.6)164 (47.1)0.492
Bladder perforation7 (2.3)10 (2.2)0.9423 (1.8)9 (2.6)0.584
Repeat SUI surgery58 (19.1)63 (14.0)0.06239 (23.5)46 (13.2)0.003
Retropubic MUS256 (84.2)359 (79.8) 138 (83.1)299 (85.9) 
Transobturator MUS48 (15.8)91 (20.2)0.12428 (16.9)49 (14.1)0.408
MUS alone194 (63.8)249 (55.3) 105 (63.3)194 (55.8) 
MUS and POP surgery110 (36.2)201 (44.7)0.0261 (36.8)154 (44.3)0.107
Vault suspension28 (9.2)63 (14.0)0.0489 (5.4)50 (14.4)0.003
Apical stg < 1 No OP122 (40.3)171 (38.0) 77 (46.4)129 (37.1) 
Apical stg > 1 No OP153 (50.5)216 (48.0) 80 (48.2)169 (48.6) 
Apical stg > 1 Apical OP25 (8.3)47 (10.4)0.1078 (4.8)40 (11.5)0.015
Mesh use27 8.9)39 (8.7)0.91815 (9.0)39 (11.2)0.456
Patient satisfaction at long-term follow up
Would not recommend surgery to friend48 (15.8)12 (2.7)<0.000141 (24.7)10 (2.9)<0.0001

Age was a risk factor for persistent urgency on univariate analysis. Women who had persistent urgency were more likely to report preoperative symptoms of bothersome urgency (74.7% versus 60.9%, P < 0.0001), nocturia of more than four episodes (6.3% versus 5.3%, P = 0.02), more likely to have body mass index > 30 (31.3% versus 24.2%, P = 0.04) and reported previous incontinence surgery (21.1% versus 14.7%, P = 0.023). Women who had a maximum flow rate of <15 m/second or post-void residual volume of >50 ml during preoperative urodynamic assessment were more likely to have persistent urgency (15.1% versus 10.0%, P = 0.037). Women who developed persistent urgency were more likely to have a preoperative diagnosis of urodynamic (mixed) stress incontinence and detrusor overactivity (29.0% versus 13.3%, P < 0.0001). Women who experienced resolution of their urgency were more likely to have undergone concomitant prolapse surgery (36.2% versus 44.7%, P = 0.02), particularly a vault suspension for apical prolapse at the time of their midurethral slings (9.2% versus 14.0%, P = 0.048). There was no difference between the type of apical prolapse surgery, using either the vaginal or the abdominal route, and outcome. Not surprisingly, women who developed persistent urgency were more likely not to recommend surgery to a friend (15.8% versus 2.7%, P < 0.0001).

Tables 1 and 2 also show the characteristics of women who reported SUI and UUI at baseline and subsequently developed persistent UUI after midurethral slings at long-term follow up. Of the 514 women, 166 had persistence urge incontinence, with the resolution rate being 67.7%. Among 27 women who reported UUI (only) at baseline, 22 had USI and five had both USI and detrusor overactivity. For women who reported UUI only (no SUI) at baseline, there was a greater proportion who described persistence of their urge incontinence, compared with women who had resolution, although this was not statistically significant (7.2% versus 4.3%, P = 0.165).

Women who had persistent UUI were more likely to report preoperative symptoms of bothersome urgency (86.5% versus 65.6%, P < 0.0001), more likely to have body mass index >30 (38.0% versus 24.7%, P = 0.021) and to have reported previous incontinence surgery (25.9% versus 14.1%, P = 0.001). They were also more likely to have a preoperative diagnosis of urodynamic (mixed) stress incontinence and detrusor overactivity (33.7% versus 19.8%, P = 0.003). Women who developed persistent UUI were more likely to have had repeat incontinence surgery (23.5% versus 13.2%, P = 0.003), although they were less likely to have had a vault suspension for apical prolapse at the time of their midurethral slings (persistent UUI 5.4% versus 14.4%, P < 0.003). There was again, no difference between the type of apical prolapse surgery, either via the vaginal or the abdominal route, and outcome. Women who developed persistent UUI were more likely not to recommend surgery to a friend (persistent UUI 24.7% versus 2.9%, P < 0.0001).

The effects of all the factors in Tables 1 and 2 on each other were examined using multivariate logistic regression modelling as previously described. Table 3 depicts the results of the multivariate analysis and lists the independent risk factors for developing persistent urgency or UUI following midurethral sling procedures. The presence of coexistent detrusor overactivity (with USI), more bothersome baseline urgency symptom severity and increasing age conferred significant odds towards developing persistent urgency following midurethral slings. Similarly, a history of incontinence surgery, more bothersome baseline urgency symptom severity, presence of coexistent detrusor overactivity (with urodynamic stress incontinence) and apical prolapse increased the odds of persistent UUI following midurethral slings. Concomitant prolapse surgery and use of transobturator midurethral slings decreased the odds of persistent urgency, whereas a concurrent apical prolapse operation at the time of the midurethral sling reduced the odds for persistent UUI.

Table 3.   Multivariate analysis—independent risk factors for persistence of urgency or urge urinary incontinence in women who had midurethral slings
 OR95% CIP value
Persistent urgency
Urodynamic USI and detrusor overactivity2.041.39–3.01<0.0001
Baseline degree of bothersome urgency1.411.10–1.780.006
Age (per year increase)1.031.02–1.04<0.0001
Transobturator sling0.610.39–0.940.024
Concomitant pelvic organ prolapse surgery0.540.38–0.75<0.0001
Persistent urgency urinary incontience
Previous SUI surgery2.181.28–3.700.004
Baseline degree of bothersome urgency1.881.38–2.56<0.0001
Urodynamic USI and detrusor overactivity1.861.18–2.930.008
Apical prolapse6.491.24–34.130.027
Apical prolapse apical op0.330.15–0.700.005

Discussion

Optimal management of MUI remains a challenge, despite the promise of the minimally invasive midurethral slings, which is highly efficacious against SUI. Persistent OAB symptoms can have a negative impact on quality of life and satisfaction after surgery.

Although MUI is said to be less responsive to interventions, such as behavioural, pharmacological or surgical, compared with pure SUI or pure UUI,15 reports of midurethral slings on detrusor overactivity and MUI are emerging. Although they excluded women with detrusor overactivity, Rezapour and Ulmsten16 reported a subjective cure of 85% in women with MUI 4 years after TVT. Similar reports have also indicated a substantial MUI resolution after midurethral slings,17,18 although cure rates are often lower than for pure SUI.19–23 There are few studies that have evaluated persistent OAB symptoms following midurethral sling procedures. With the aim of evaluating resolution of detrusor overactivity or UUI, Botros et al.24 performed a logistic regression analysis involving 276 women following midurethral slings with follow up at only 14 weeks. She found that rates of resolution of detrusor overactivity/UUI did not differ between those who underwent retropubic or transobturator slings. The univariate analysis by Segal et al.25 evaluated OAB symptoms after TVT in 98 women with an average follow up of 7 months. They found that the urgency component resolved in 63% of women. Our analysis included 754 women who had midurethral slings, with a mean follow up of 50 months. In this study, the overall subjective rate for persistent urgency and persistent UUI was 40.3% and 32.3% respectively, which is similar to figures (44–54%) reported in the recently updated American Urological Association guidelines for female SUI.26

Our study showed that the presence of preoperative USI with detrusor overactivity in women undergoing midurethral slings was a significant independent risk factor for persistent urgency or UUI, which is consistent with other studies.24,27–29 Furthermore, use of transobturator midurethral slings decreases the risk of postoperative urgency. A retrospective analysis24 of 276 women (99 TVT, 52 SPARC, 125 Monarc), reported a higher rate of deterioration of preoperative UUI for (retropubic) TVT/SPARC at 14–16%, compared with 6% for (transobturator) Monarc (P = 0.02). The same group later reported a multivariate logistic regression model29 for 291 women, demonstrating TVT (odds ratio [OR] 2.18, 95% CI 1.07–4.44) and SPARC (OR 1.51, 95% CI 0.61–3.71) are associated with higher odds of persistent postoperative detrusor overactivity compared with Monarc. It is conceivable that the retropubic midurethral slings has a ‘U-shaped’ profile, compared with the ‘H’ or ‘hammock-like’ shape for the transobturator midurethral slings, consequently making it tighter, which may contribute to the higher rate of persistent OAB after surgery. This is consistent with results from a meta-analysis of randomised controlled trials comparing transobturator and retropubic midurethral slings, which showed a lower odds of postoperative OAB symptoms (OR 0.55, 95% CI 0.35–0.88)30. Interestingly, in a prospective randomised study31 of women with USI and intrinsic sphincter deficiency comparing the retropubic TVT sling with the transobturator Monarc sling, the resolution and new development of OAB symptoms at 6 months postoperatively was not significantly different.

We found age to be an independent predictor of persistent urgency following midurethral slings for women with MUI. This is not surprising given that detrusor overactivity is known to be more prevalent in the elderly population.32 It is plausible that age-related changes in bladder structure and function could be responsible for the high prevalence of OAB in this group.33 Further, women who ascribed a higher degree of symptom severity for OAB symptoms, have a higher risk for persistent OAB following midurethral slings. A history of anti-incontinence surgery is a risk factor for persistence of urgency or UUI in our study. Although it is plausible that this is caused by a combination of a degree of obstruction and the presence of a sling, our data did not show a significant difference in the de novo rate of OAB symptoms in women who had low flow rate (<15 ml/second) or high post-void residual volume (>50 ml) following midurethral slings, on multivariate analysis. It could be postulated that previous SUI surgery may have caused some denervation during dissection, culminating in an excess of postoperative persistent OAB symptoms.

Our multivariate analysis demonstrated that women with apical prolapse had increased odds of persistent UUI following midurethral slings and women who underwent concomitant apical prolapse operations (such as uterosacral suspension, sacrospinous fixation, abdominal scarocolpopexy), had a decreased risk of developing persistent UUI. Perhaps vaginal prolapse of the anterior and apical compartment does cause OAB symptoms, possibly as the result of distortion of the bladder base or relative outlet obstruction, observations that are supported by several studies. Investigators of the Be-Dri34 study reported their multivariate analysis of 307 women to determine predictors of outcome in the treatment of UUI. They found that poorer vaginal support predicted successful OAB outcomes after 6 months. In the analysis by de Boer et al.35 of 505 women who underwent prolapse surgery, postoperative urinary frequency and urgency appeared less common in women with higher preoperative prolapse stage. Resolution of OAB symptoms was also reported in other studies, following surgery for prolapse36,37 or use of vaginal support pessaries.38

The strength of this analysis includes a large cohort of well-described women, with a mean follow up of more than 4 years, who underwent standardised evaluation and had surgery performed by a number of surgeons. This allows for a more robust multivariate analysis in the assessment of predictive preoperative factors for postoperative OAB symptoms. Study limitations are consistent with the retrospective nature of its design, although data collected using the same proforma during the study period should help with consistency. We acknowledge the absence of ‘objective’ parameters in the postoperative evaluation of women, such as urodynamics, pad test and voiding diaries, but we would contend that there are no reliable ‘objective’ diagnostic criteria for persistent urgency or UUI. We accept that the patient-reported outcomes were collected using a modified questionnaire that has not been formally validated.

The impact of persistent urgency or UUI on outcomes of surgery for SUI has several important implications. Given the results of our analysis, it seems prudent to carefully assess baseline symptom severity, conduct careful evaluation for significant pelvic organ prolapse, urodynamic investigations and offer appropriate midurethral slings and prolapse surgery to optimise global patient outcomes in women presenting for midurethral slings, in addition to reiterating the importance of detailed preoperative counselling.

Conclusions

The presence of coexistent detrusor overactivity, baseline urgency symptoms, increasing age and previous incontinence surgery increased the risk of persistent urgency or UUI after midurethral sling, whereas use of transobturator sling and concomitant apical prolapse surgery decreased the risk. Urodynamic parameters, baseline urgency symptom severity, midurethral sling route and concomitant prolapse operation are important predictors of persistent urgency or UUI following midurethral slings. Overall satisfaction with the midurethral sling operation was significantly less in women who had persistent urgency or UUI following the procedure.

Disclosure of interests

There was no outside funding or technical assistance with the production of this article. JL, PD, AR and YL are investigators in an ongoing randomised controlled trial of midurethral slings and have received external research grants from American Medical Systems.

Contribution to authorship

The research question was conceived by JL with the research methodology discussed and approved by PD, AR and YL. AP conducted the statistical analysis. Data collection and management were performed by KS and JL. All the authors contributed to writing the manuscript and approved the final version.

Details of ethics approval

The Mercy Hospital for Women hospital ethics committee approved the project [R08/08].

Funding

There was no external funding or technical assistance with the production of this article.

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