title: Bladder ultrasonography for diagnosing detrusor overactivity: test accuracy study and economic evaluation.
abstract: BACKGROUND
  Urodynamics (UDS) has been considered the gold standard test for detrusor overactivity (DO) in women with an overactive bladder (OAB). Bladder ultrasonography to measure bladder wall thickness (BWT) is less invasive and has been proposed as an alternative test.
  
  
  OBJECTIVE
  To estimate the reliability, reproducibility, accuracy and acceptability of BWT in women with OAB, measured by ultrasonography, in the diagnosis of DO; to explore the role of UDS and its impact on treatment outcomes; and to conduct an economic evaluation of alternative care pathways.
  
  
  METHODS
  A cross-sectional test accuracy study.
  
  
  METHODS
  22 UK hospitals.
  
  
  METHODS
  687 women with OAB.
  
  
  METHODS
  BWT was measured using transvaginal ultrasonography, and DO was assessed using UDS, which was performed blind to ultrasonographic findings. Intraobserver and interobserver reproducibility were assessed by repeated measurements from scans in 37 and 57 women, respectively, and by repeated scans in 27 women. Sensitivity and specificity were computed at pre-specified thresholds. The smallest real differences detectable of BWT were estimated using one-way analysis of variance. The pain and acceptability of both tests were evaluated by a questionnaire. Patient symptoms were measured before testing and after 6 and 12 months using the International Consultation on Incontinence modular Questionnaire Overactive Bladder (short form) (ICIQ-OAB) questionnaire and a global impression of improvement elicited at 12 months. Interventions and patient outcomes were analysed according to urodynamic diagnoses and BWT measurements. A decision-analytic model compared the cost-effectiveness of care strategies using UDS, ultrasonography or clinical history, estimating the cost per woman successfully treated and the cost per quality-adjusted life-year (QALY).
  
  
  RESULTS
  BWT showed very low sensitivity and specificity at all pre-specified cut-off points, and there was no evidence of discrimination at any threshold (p = 0.25). Extensive sensitivity and subgroup analyses did not alter the interpretation of these findings. The smallest detectable difference in BWT was estimated to be 2 mm. Pain levels following both tests appeared relatively low. The proportion of women who found the test 'totally acceptable' was significantly higher with ultrasonography than UDS (81% vs. 56%; p < 0.001). Overall, subsequent treatment was highly associated with urodynamic diagnosis (p < 0.0001). There was no evidence that BWT had any relationship with the global impression of improvement responses at 20 months (p = 0.4). Bladder ultrasonography was more costly and less effective than the other strategies. The incremental cost-effectiveness ratio (ICER) of basing treatment on the primary clinical presentation compared with UDS was £491,500 per woman successfully treated and £60,200 per QALY. Performing a UDS in those women with a clinical history of mixed urinary incontinence had an ICER of £19,500 per woman successfully treated and £12,700 per QALY compared with the provision of urodynamic to all women. For DO cases detected, UDS was the most cost-effective strategy.
  
  
  CONCLUSIONS
  There was no evidence that BWT had any relationship with DO, regardless of the cut-off point, nor any relationship to symptoms as measured by the ICIQ-OAB. Bladder ultrasonography has no diagnostic or prognostic value as a test in this condition. Furthermore, despite its greater acceptability, BWT measurement was not sufficiently reliable or reproducible.
  
  
  BACKGROUND
  Current Controlled Trials ISRCTN46820623.
  
  
  BACKGROUND
  This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 7. See the NIHR Journals Library website for further project information.
authors.affiliation: School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.
authors.forename: Suneetha
authors.initials: S
authors.lastname: Rachaneni
authors.affiliation: Birmingham Women's NHS Foundation Trust, Birmingham, UK.
authors.forename: Shanteela
authors.initials: S
authors.lastname: McCooty
authors.affiliation: Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK.
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Middleton
authors.affiliation: Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Parker
authors.affiliation: School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.|Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK.
authors.forename: Jane P
authors.initials: JP
authors.lastname: Daniels
authors.affiliation: School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.|Birmingham Women's NHS Foundation Trust, Birmingham, UK.
authors.forename: Arri
authors.initials: A
authors.lastname: Coomarasamy
authors.affiliation: School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.|Birmingham Women's NHS Foundation Trust, Birmingham, UK.
authors.forename: Tina S
authors.initials: TS
authors.lastname: Verghese
authors.affiliation: Birmingham Women's NHS Foundation Trust, Birmingham, UK.
authors.forename: Moji
authors.initials: M
authors.lastname: Balogun
authors.affiliation: Health Economics Unit, University of Birmingham, Birmingham, UK.
authors.forename: Ilias
authors.initials: I
authors.lastname: Goranitis
authors.affiliation: Health Economics Unit, University of Birmingham, Birmingham, UK.
authors.forename: Pelham
authors.initials: P
authors.lastname: Barton
authors.affiliation: Health Economics Unit, University of Birmingham, Birmingham, UK.
authors.forename: Tracy E
authors.initials: TE
authors.lastname: Roberts
authors.affiliation: Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, UK.|Public Health, Epidemiology and Biostatistics, University of Birmingham, Birmingham, UK.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Deeks
authors.affiliation: School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.|Birmingham Women's NHS Foundation Trust, Birmingham, UK.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Latthe
mesh_terms: D000328:Adult; D000368:Aged; D003362:Cost-Benefit Analysis; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D013673:Technology Assessment, Biomedical; D016896:Treatment Outcome; D014463:Ultrasonography; D053201:Urinary Bladder, Overactive / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014563:Urodynamics / Q000502:physiology*