title: The minimum important difference for the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form in women with stress urinary incontinence.
abstract: BACKGROUND
  Minimum important difference (MID) estimates the minimum degree of change in an instrument's score that correlates with a patient's subjective sense of improvement. We aimed to determine the MID for the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) using both anchor based and distribution based methods derived using data from the Trial of Midurethral Slings (TOMUS).
  
  
  METHODS
  Instruments for the anchor-based analyses included the urogenital distress inventory (UDI), incontinence impact questionnaire (IIQ), patient global impression of improvement (PGI-I), incontinence episodes (IE) on 7-day bladder diary, and satisfaction with surgical results. After confirming moderate correlation (r ≥ 0.3) of ICIQ-UI SF and each anchor, MIDs were determined by calculating the difference between the mean instrument scores for individuals with the smallest amount of improvement and with no change. The distribution-based method of MID assessment was applied using effect sizes of 0.2 and 0.5 SD (small to medium effects). Triangulation was used to examine these multiple MID values in order to converge on a small range of values.
  
  
  RESULTS
  Anchor-based MIDs range from -4.5 to -5.7 at 12 months and from -3.1 to 4.3 at 24 months. Distribution-based MID values were lower. Triangulation analysis supports a MID of -5 at 12 months and -4 at 24 months.
  
  
  CONCLUSIONS
  The recommended MIDs for ICIQ-UI SF are -5 at 12 months and -4 at 24 months. In surgical patients, ICIQ-UI SF score changes that meet these thresholds can be considered clinically meaningful.
authors.affiliation: William Beaumont Hospital, Royal Oak, Michigan.
authors.forename: Larry T
authors.initials: LT
authors.lastname: Sirls
authors.forename: Sharon
authors.initials: S
authors.lastname: Tennstedt
authors.forename: Linda
authors.initials: L
authors.lastname: Brubaker
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Ingrid
authors.initials: I
authors.lastname: Nygaard
authors.forename: David D
authors.initials: DD
authors.lastname: Rahn
authors.forename: Jonathan
authors.initials: J
authors.lastname: Shepherd
authors.forename: Holly E
authors.initials: HE
authors.lastname: Richter
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007390:International Agencies; D008875:Middle Aged; D017060:Patient Satisfaction; D011788:Quality of Life; D012017:Referral and Consultation; D012720:Severity of Illness Index; D053825:Suburethral Slings; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014550:Urinary Incontinence, Stress / Q000601:surgery*
keywords: ICIQ-UI SF; midurethral slin; minimum important difference; quality of life; urinary incontinence