An overactive bladder symptom and health-related quality of life short-form: validation of the OAB-q SF

Aims: The Overactive Bladder Questionnaire (OAB-q) has demonstrated robust psychometric properties in continent and incontinent OAB patients. However, there is a need for a short-form of this instrument for settings where completing the full OAB-q may be too burdensome. The purpose of this manuscript is to describe the validation of the OAB-q short-form.

Methods: Three studies were used to derive and validate the OAB-q SF: a 12-week, multicenter, open-label clinical trial of tolterodine ER (N = 865 incontinent OAB [I-OAB]; the "Noble Nested Case-Control" [NCC] study; N = 523 healthy controls; N = 396 OAB); and a test-retest validation study (N = 47). Rasch analysis and confirmatory factor analysis (CFA) were performed to assess the subscale structure, and the psychometric performance of the resulting scales was evaluated.

Results: Based on the Rasch analysis, 6-items were retained in the OAB-q SF Symptom Bother Scale and 13-items were retained in the HRQL scale. CFAs showed excellent model fit and internal consistency in the study populations. Both scales demonstrated good convergent validity, discriminant validity, internal reliability, reproducibility, and responsiveness to change. The OAB-q SF scales clearly differentiated among I-OAB, C-OAB, and healthy controls.

Conclusion: 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.