INVESTIGATE-I (INVasive Evaluation before Surgical Treatment of Incontinence Gives Added Therapeutic Effect?): a mixed-methods study to assess the feasibility of a future randomised controlled trial of invasive urodynamic testing prior to surgery for stress urinary incontinence in women

How should prospective research be designed to legitimately assess the value of urodynamic studies in female urinary incontinence?

AIMS

Since formal evidence demonstrating the value of urodynamic studies (UDS) in functional urology remains elusive, we aimed to consider how best to design robust research for this purpose in female urinary incontinence.

METHODS

An expert group was convened to debate the following considerations: (a) precedents for formally proving the value of a gold standard diagnostic test, (b) key research principles, (c) defining a study population, (d) selecting endpoints, (e) defining interventional and controls arms, (f) blinding, (g) powering the study, and (h) duration of follow-up. In each case, we considered the strengths and weaknesses of different approaches in terms of scientific validity, ethical acceptability, practicality, and likelihood of bias.

RESULTS

We agreed that unlike evaluating therapies, attempting to judge the value of a diagnostic test based on eventual treatment success is conceptually flawed. Nonetheless, we explored the design of a hypothetical randomized controlled trial for this purpose, agreeing that: (1) the study population must sufficiently reflect its real-world counterpart; (2) clinical endpoints should include not only continence status but also other lower urinary tract symptoms and risks of management; (3) participants in the interventional arm should receive individualized management based on their UDS findings; (4) the most scientifically valid approach to the control arm-empiric treatment-is ethically problematic; (5) sufficient statistical power is imperative; and (6) ≥ 2 years' follow-up is needed to assess the long-term impact of management.

CONCLUSIONS

Although a perfect protocol does not exist, we recommend careful consideration of our observations when reflecting on past studies or planning new prospective research.

Does pre-operative urodynamics lead to better outcomes in management of urinary incontinence in women? A linked systematic review and meta-analysis

The use of preoperative urodynamics as a standard investigation for urinary incontinence (UI) has long been a subject of debate, with a lack of robust evidence to demonstrate improved patients' outcomes. We aim to compare the clinical and cost effectiveness of urodynamics versus office clinical evaluation only, prior to the treatment of UI. We conducted three linked systematic reviews and meta-analyses of randomised controlled trials (RCTs) comparing urodynamics assessment versus clinical evaluation only in women prior to 1) non-surgical treatment of UI, 2a) surgical treatment of stress urinary incontinence (SUI) and 2b) invasive treatment for overactive bladder (OAB). Women with severe pelvic organ prolapse, previous continence surgery and neuropathic bladder were excluded. Primary outcomes were patient-reported and objective success post-treatment. Secondary outcomes were adverse events, quality of life, sexual function and health economic measures. We searched MEDLINE, Embase and Cochrane Central Register of Controlled Trials databases for each category, which was last updated on January 2019. Study selection, risk of bias assessment and data extraction were performed independently by two reviewers. The random effects model was used to assess risk ratio and mean difference with 95% confidence interval. Statistical heterogeneity was assessed by I² statistics and the quality of evidence by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Four RCTs compared urodynamics versus clinical evaluation only prior to non-surgical management of UI. Treatment consisted of pelvic floor muscle training, with or without pharmacological therapy. Meta-analysis of 150 women showed no evidence of significant difference in the patient-reported and objective success rates between groups (P = 0.520, RR: 0.91, 95% Cl 0.69-1.21, I² = 0% and P = 0.470, RR:0.87, 95% Cl 0.59-1.28, I² = n/a, respectively). Seven RCTs were identified for surgical management of SUI. The majority of women underwent mid-urethral tape procedures (retropubic or transobturator approach). Meta-analysis of 1149 women showed no evidence of significant difference in patient-reported (P = 0.850, RR:1.01, 95% CI 0.88-1.16, I² = 53%) and objective success between groups (P = 0.630, RR:1.02, 95% CI 0.95-1.08, I² = 28%). There was no significant difference in incidence of voiding dysfunction, de novo urgency, and urinary tract infection between groups. No RCTs were identified for invasive management of OAB. In conclusion, limited evidence shows that routine urodynamics prior to non-surgical management of UI or surgical management of SUI is not associated with improved treatment outcomes, when compared to clinical evaluation only. Well-designed clinical trials are needed to evaluate the clinical and cost-effectiveness of routine urodynamics prior to surgical management of SUI and OAB.

Invasive urodynamic testing prior to surgical treatment for stress urinary incontinence in women: cost-effectiveness and value of information analyses in the context of a mixed methods feasibility study

BACKGROUND

INVESTIGATE-I (INVasive Evaluation before Surgical Treatment of Incontinence Gives Added Therapeutic Effect?) was a mixed methods study to assess the feasibility of a future randomised controlled trial of invasive urodynamic testing (IUT) prior to surgery for stress urinary incontinence (SUI) in women. Here we report one of the study's five components, with the specific objectives of (i) exploring the cost-effectiveness of IUT compared with clinical assessment plus non-invasive tests (henceforth described as 'IUT' and 'no IUT' respectively) in women with SUI or stress-predominant mixed urinary incontinence (MUI) prior to surgery, and (ii) determining the expected net gain (ENG) from additional research.

METHODS

Study participants were women with SUI or stress-predominant MUI who had failed to respond to conservative treatments recruited from seven UK urogynaecology and female urology units. They were randomised to receive either 'IUT' or 'no IUT' before undergoing further treatment. Data from 218 women were used in the economic analysis. Cost utility, net benefit and value of information (VoI) analyses were performed within a randomised controlled pilot trial. Costs and quality-adjusted life years (QALYs) were estimated over 6 months to determine the incremental cost per QALY of 'IUT' compared to 'no IUT'. Net monetary benefit informed the VoI analysis. The VoI estimated the ENG and optimal sample size for a future definitive trial.

RESULTS

At 6 months, the mean difference in total average cost was £138 (p = 0.071) in favour of 'IUT'; there was no difference in QALYs estimated from the SF-12 (difference 0.004; p = 0.425) and EQ-5D-3L (difference - 0.004; p = 0.725); therefore, the probability of IUT being cost-effective remains uncertain. The estimated ENG was positive for further research to address this uncertainty with an optimal sample size of 404 women.

CONCLUSIONS

This is the largest economic evaluation of IUT. On average, up to 6 months after treatment, 'IUT' may be cost-saving compared to 'no IUT' because of the reduction in surgery following invasive investigation. However, uncertainty remains over the probability of 'IUT' being considered cost-effective, especially in the longer term. The VoI analysis indicated that further research would be of value.

TRIAL REGISTRATION

ISRCTN. ISRCTN71327395. Registered 7 June 2010.

Understanding variations in patient screening and recruitment in a multicentre pilot randomised controlled trial: a vignette-based study

BACKGROUND

The INVESTIGATE-I study was designed to inform a future definitive randomised trial of invasive urodynamic testing, compared to basic clinical assessment with noninvasive tests prior to surgical treatment, in women with stress urinary incontinence or stress-predominant mixed urinary incontinence. In a pilot randomised controlled trial, women from seven participating sites were screened, consented and randomised. Overall, 771 patients were identified from clinic notes and correspondence as being potential recruits and were sent the Patient Information Leaflet. Of those screened, 284 were deemed eligible, giving an overall 'screen positive' rate of 37 %. The numbers screened at individual centres varied between 14 and 399; the 'screen positive' rate varied between 22 and 79 % and the percentage of eligible women recruited varied between 55 and 100 %. The aim of this additional substudy was to explore why 'screen positive' rates may have varied so widely between apparently similar sites.

RESULTS

All 11 trial staff involved in screening in the seven recruiting sites were asked to evaluate a series of 20 identical vignettes, mainly based on actual general practitioner referral letters. Of the vignettes, 16 mentioned one or more definite inclusion criteria; the remainder had possible inclusions. Four had definite exclusions; 12 had possible exclusions. Free-text comments were sought to clarify the screeners' decisions. For six vignettes everyone agreed that the patient was eligible; for one all agreed she was not eligible; the breakdown for the remainder was mixed. Free-text comments illuminated uncertainties that may have led to variability in judging potential eligibility.

CONCLUSIONS

Variability in judgements about potential trial eligibility highlights the importance of explicit and objective inclusion and exclusion criteria, and of agreed strategies for making judgements when information is missing. During the development and planning of trials, vignettes might be a valuable tool for training those involved in screening and recruiting patients, for identifying potential problems and ensuring greater consistency in the application of eligibility criteria.

TRIAL REGISTRATION

ISTCTN registry: ISRCTN71327395 , registered on 7 June 2010.

Evaluation and Classification of Stress Urinary Incontinence: Current Concepts and Future Directions

CONTEXT

Stress urinary incontinence (SUI) is a common and bothersome problem that frequently requires operative management. Over the past two decades, novel techniques have been introduced into clinical practice. With the greater variety of surgical options now available, there is an increasing focus on selecting the appropriate procedure for the individual patient based on the likely underlying pathophysiologic mechanism.

OBJECTIVE

To review the methods used in the evaluation of SUI and the proposed classification systems.

EVIDENCE ACQUISITION

A search of the PubMed database for the relevant search terms was conducted, and selected articles were retrieved and reviewed.

EVIDENCE SYNTHESIS

Standardised terminology for the description of SUI has been produced by the International Continence Society describing the problem in terms of symptoms, clinical signs, and urodynamic observations. The two major pathophysiologic theories that have emerged over the past 50 yr, urethral hypermobility and intrinsic sphincteric deficiency, have influenced the development and adoption of surgical techniques. It is now recognised that these two entities are not dichotomous but often coexist. The primary aim of the evaluation of the patient presenting with SUI is to confirm the diagnosis and assess symptom severity before instituting conservative treatments. Secondary evaluation consists of more sophisticated techniques that assess anatomy of the bladder neck and urethra under rest and stress (eg, videourodynamics, ultrasound) or direct or indirect physiologic measures of the integrity of the sphincter mechanism.

CONCLUSIONS

Classification of patients with SUI into distinct groups based on probable pathophysiologic mechanism could help guide the choice of surgical procedure, but current systems are likely too simplistic, and methods of assessment lack standardisation in techniques and sensitivity.

PATIENT SUMMARY

Urinary leakage on exertion, termed stress incontinence, is a common problem that affects many women. There is a need to develop better ways of categorising the underlying causes of leakage to ensure that patients receive the optimal treatments.

Trial participation as avoidance strategy: a qualitative study

BACKGROUND

Trial participation decisions are often influenced by expectations of potential benefit. Attention has focused on trial participation as a means of securing something seen as desirable, such as experimental treatment. In contrast, we consider a case in which one trial arm involved receiving less than usual care. We explore how this influenced participants' decisions to participate.

METHODS

Semi-structured interviews with 29 women participating in a pilot trial comparing invasive urodynamic testing (typically normal care) to basic clinical assessment with non-invasive tests, prior to surgical treatment for stress urinary incontinence. Analysis was based on the constant comparative method.

RESULTS

Invasive tests were something many were aware of and worried about. Participants understood that trial participation meant they might avoid having these tests, and for about one-third, this was the primary factor motivating participation. A further third mentioned they were not looking forward to tests (if allocated to them) or were lucky to have missed them (if allocated to basic clinical assessment). None of the women appeared to have discussed their desire to avoid having invasive tests with their clinicians.

CONCLUSIONS

In contrast to cases in which trial participation is motivated by the wish to secure an intervention not otherwise available, this study reports the opposite - trial participation as an opportunity to avoid having something regarded as undesirable. The option to decline a particular intervention should always be available, and care must be taken to ensure that potential participants are aware that trial participation is not the only possible means of avoidance.