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

Abstract

BackgroundThe position of invasive urodynamic testing in the diagnostic pathway for urinary incontinence (UI) is unclear. Systematic reviews have called for further trials evaluating clinical utility, although a preliminary feasibility study was considered appropriate.ObjectivesTo inform the decision whether or not to proceed to a definitive randomised trial of invasive urodynamic testing compared with clinical assessment with non-invasive tests, prior to surgery in women with stress UI (SUI) or stress predominant mixed UI (MUI).DesignA mixed-methods study comprising a pragmatic multicentre randomised pilot trial; economic evaluation; survey of clinicians’ views about invasive urodynamic testing; qualitative interviews with clinicians and trial participants.SettingUrogynaecology, female urology and general gynaecology units in Newcastle, Leicester, Swansea, Sheffield, Northumberland, Gateshead and South Tees.ParticipantsTrial recruits were women with SUI or stress predominant MUI who were considering surgery after unsuccessful conservative treatment. Relevant clinicians completed two online surveys. Subsets of survey respondents and trial participants took part in separate qualitative interview studies.InterventionsPilot trial participants were randomised to undergo clinical assessment with non-invasive tests (control arm); or assessment as controls, plus invasive urodynamic testing (intervention arm).Main outcome measuresConfirmation that units can identify and recruit eligible women; acceptability of investigation strategies and data collection tools; acquisition of outcome data to determine the sample size for a definitive trial. The proposed primary outcome for the definitive trial was International Consultation on Incontinence Modular Questionnaire (ICIQ) Female Lower Urinary Tract Symptoms (ICIQ-FLUTS) (total score) 6 months after surgery or the start of non-surgical treatment; secondary outcomes included: ICIQ-FLUTS (subscales); ICIQ Urinary Incontinence Short Form; ICIQ Lower Urinary Tract Symptoms Quality of Life; Urogenital Distress Inventory; EuroQol-5D; costs, quality-adjusted life-years (QALYs) and incremental cost per QALY, Short Form 12; 3-day bladder diary.ResultsOf 284 eligible women, 222 (78%) were recruited; 165/219 (75%) returned questionnaires at baseline and 125/200 (63%) who were sent questionnaires at follow-up. There were few missing data items in returned questionnaires, with individual outcome scales calculable for 81%–94%. Most women underwent surgery; management plans were changed in 19 (19%) participants following invasive urodynamic testing. Participant Costs Questionnaires were returned by 53% 6 months after treatment; complete data to undertake cost–utility analysis were available in 27% (intervention) and 47% (control). While insufficient to recommend changes in practice, the results suggest further research would be valuable. All clinicians responding to the survey had access to invasive urodynamic testing, and most saw it as essential prior to surgery in women with SUI with or without other symptoms; nevertheless, 70% considered the research question underlying INVESTIGATE important and most were willing to randomise patients in a definitive trial. Participants interviewed were positive about the trial and associated documentation; the desire of some women to avoid invasive urodynamic testing contrasted with opinions expressed by clinicians through both survey and interview responses.ConclusionsAll elements of a definitive trial and economic evaluation were rehearsed; several areas for protocol modification were identified. Such a trial would require to 400–900 participants, depending on the difference in primary outcome sought.Future workA definitive trial of invasive urodynamic testing versus clinical assessment prior to surgery for SUI or stress predominant MUI should be undertaken.Trial registrationCurrent Controlled Trials ISRCTN71327395.FundingThe National Institute for Health Research Health Technology Assessment programme.

Trial participation as avoidance strategy: a qualitative study

“…We conducted semi‐structured interviews with women who had participated in a pilot trial comparing invasive urodynamic testing to basic clinical assessment with non‐invasive tests prior to surgical treatment for urinary incontinence . While we also invited all women who did not agree to join the pilot trial (59) as soon as possible thereafter for interview, none agreed to do so.…”

“…The INVESTIGATE‐I study was a mixed methods feasibility study including a pragmatic multicentre ‘rehearsal’ pilot randomized controlled trial (RCT) of invasive urodynamic testing compared to basic clinical assessment before surgical treatment for stress urinary incontinence in women; it was funded under the UK National Institute for Health Research Health Technology Assessment programme (NIHR‐HTA) programme . Urinary incontinence, while rarely life‐threatening, may seriously influence the physical, psychological and social well‐being of affected individuals.…”

Authors' reply re: Does preoperative urodynamics improve outcomes for women undergoing surgery for stress urinary incontinence? A systematic review and meta‐analysis

“…We disagree with their comment on uroflowmetry, as two of the randomised controlled trials (RCTs) in our systematic review have incorporated uroflowmetry as a part of their evaluation …”

Re: Hilton P, Bryant A, Howel D, McColl E, Buckley BS, Lucas MG, et al. Assessing professional equipoise and views about a future clinical trial of invasive urodynamics prior to surgery for stress urinary incontinence in women: A survey within a mixed methods feasibility study. Neurourol Urodyn. 2012;31(8):1223–30

“…Hence, they indicated that larger definitive trials are still needed in which people are randomly allocated to management according to urodynamic findings or to management based on history and clinical examination to determine whether the performance of urodynamics results in higher continence rates after treatment . It is gratifying therefore that we found evidence that sufficient numbers of clinicians remain prepared to take part, to make a definitive trial in the UK not only highly relevant to clarifying practice in this area, but also feasible …”

“…As part of the mixed methods feasibility study INVESTIGATE‐I, in August 2011 we undertook a survey of members of the British Society of Urogynaecology (BSUG) and the British Association of Urological Surgeons—Section of Female, Neurological and Urodynamic Urology (BAUS‐SFNUU). This sought to establish their views on the place of invasive urodynamic testing (IUT) in female lower urinary tract symptoms and their level of support for a future randomised controlled trial of IUT prior to surgery for stress urinary incontinence (SUI) .…”