Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Randomized Controlled Trial
. 2011 Sep;30(7):1319-24.
doi: 10.1002/nau.21028. Epub 2011 May 11.

Minimum important difference for validated instruments in women with urge incontinence

Keisha Y Dyer  1 , Yan Xu, Linda Brubaker, Ingrid Nygaard, Alayne Markland, David Rahn, Toby C Chai, Ann Stoddard, Emily Lukacz; Urinary Incontinence Treatment Network (UITN)
Collaborators, Affiliations
Randomized Controlled Trial

Minimum important difference for validated instruments in women with urge incontinence

Keisha Y Dyer et al. Neurourol Urodyn. 2011 Sep.

Abstract

Aims: Minimum important difference (MID) estimates the minimum degree of change in an instrument's score that correlates with subjective sense of improvement. The aim of this study was to estimate the MID for the Urogenital Distress Inventory (UDI), Incontinence Impact Questionnaire (IIQ) and Overactive Bladder Questionnaire (OAB-q) using anchor and distribution-based approaches in patients with urge-predominant incontinence and whether MID changes over time.

Methods: This was a sub-analysis of a multi-center trial of 307 women with pure urge (11) or urge-predominant (296) incontinence who completed condition-specific instruments 10 weeks and 8 months after randomization to anticholinergic medication with or without behavioral therapy. We applied anchor-based methods only when the Kendall's rank correlations between the anchors (Global Perception of Improvement (GPI), Patient Satisfaction Questionnaire (PSQ), and incontinence episodes) and the incontinence instruments (UDI, UDI irritative subscale, IIQ, and OAB-q subscales) were ≥ 0.3. We applied three distribution-based methods to all instruments: effect sizes of ± 0.2 SD (small) and ± 0.5 SD (medium), and standard error of measurement of ± 1. Analyses were performed at both time points.

Results: Anchor-based MIDs for the UDI ranged from -35 to -45 and -15 to -25 for the irritative subscale distribution-based methods MIDs for UDI and IIQ ranged between -10 to -25 and -19 to -49, respectively, reflective of a reduction in bother and symptom severity (SS). OAB-q subscale MIDs ranged from +5 to +12, denoting improved quality of life (HRQL) and -13 to -25, consistent with a reduction in SS.

Conclusions: The MID in women with urge-predominant UI for the UDI and UDI irritative are -35 and -15. Our findings are consistent with previously reported MIDs for the OAB-q subscales. Distribution-based method MIDs are lower values than anchor-based values. The MID did not typically change over the time.

Trial registration: ClinicalTrials.gov NCT00090584.

PubMed Disclaimer

References

    1. Hartmann KE, McPheeters ML, Biller DH, et al. Evidence report/technology assessment no 187. Rockville, MD: Agency for Healthcare Research and Quality. AHRQ publication no 09-E017; 2009. [4 Dec 2009]. Treatment of overactive bladder in women. Accessed at http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/bladder.pdf.
    1. Irwin DE, Milsom I, Kopp Z, Abrams P. Symptom bother and health care-seeking behavior among individuals with overactive bladder. Eur Urol. 2008;53(5):1029–37. - PubMed
    1. Hu TW, Wagner TH, Bentkover JD, Leblanc K, Zhou SZ, Hunt T. Costs of urinary incontinence and overactive bladder in the United States: a comparative study. Urology. 2004;63(3):461–465. - PubMed
    1. Coyne KS, Zhou Z, Thompson C, Versi E. The impact on health-related quality of life of stress, urge and mixed urinary incontinence. BJU Int. 2003;92:731–5. - PubMed
    1. Shumaker SA, Wyman JF, Uebersax J, McClish DK, Fantl JA. Health-related quality of life measures for women with urinary incontinence: the Incontinence Impact Questionnaire and the Urogenital Distress Inventory. Qual Life Res. 1994;3:291–306. - PubMed

Publication types

MeSH terms

Substances

Associated data