A shortened version of the OAB-q was derived from the original questionnaire through item response theory analyses. This "short form," called the OAB-q SF, consists of a 6-item symptom bother scale and a 13-item HRQL scale. The OAB-q SF has been included in the International Consultation on Incontinence Modular Questionnaire (ICIQ-OAB) module to assess the impact of OAB on patients' lives. Development and validation of the OAB-q SF was recently described in a presentation at the 2004 Meeting of the International Continence Society and the International Urogynecological Society.
The OAB-q SF was derived from the original OAB-q to reduce respondent burden while retaining the reliability, validity, and responsiveness of the OAB-q. It has been validated retrospectively using data from a cross-sectional survey (n = 919) and a 12-week clinical trial (n = 865).
Rasch analysis (or Item Response Theory) was used to identify the questions or items within the original OAB-q that perform best across the spectrum of OAB symptoms. Items that worked well among patients with mild symptoms as well as severe symptoms were retained. Factor structure of the short form was examined using confirmatory factor analysis.
The 8-item symptom bother scale of the OAB-q was reduced to 6 items, and the 25-item HRQL scale of the OAB-q was reduced to 13 items.
The OAB-q SF demonstrated good internal consistency reliability, concurrent validity, discriminant validity, and responsiveness. These results have been presented at the 2004 Joint Meeting of the International Continence Society and the International UroGynecological Association (IUGA).
Reliability and Responsiveness of the OAB-q and OAB-q SF
|
|
# of items
|
Cronbach's α
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Effect Size
|
|
Subscale
|
OAB-q
|
OAB-q SF
|
OAB-q
|
OAB-q SF
|
OAB-q
|
OAB-q SF
|
|
Symptom bother
|
8
|
6
|
0.93
|
0.91
|
-1.23
|
-1.14
|
|
HRQL
|
25
|
13
|
0.97
|
0.95
|
0.97
|
0.99
|
The OAB-q SF captures the full spectrum of OAB symptom bother and HRQL impact with good reliability, validity, and responsiveness, while being less time-consuming for patients to complete.
The OAB-q SF will be incorporated into the International Consultation on Incontinence Modular Questionnaire (ICIQ) as the "ICIQ-OAB."
