Psychometric validation of an overactive bladder symptom and health-related quality of life questionnaire: the OAB-q.

OBJECTIVE: Overactive bladder (OAB) is characterized by symptoms of urinary frequency and urgency, with and without incontinence, and has been shown to have significant impact on health-related quality of life (HRQL). Currently, no OAB-specific questionnaires exist to evaluate all symptoms of OAB; thus we sought to evaluate the psychometric properties of a newly developed OAB HRQL questionnaire.
METHODS: The 33-item, self-administered OAB-q contains a symptom bother and HRQL scale. Both the OAB-q and SF-36 were completed by participants from two sources: (1) a community sample who screened positive for OAB in a random-digit dial telephone survey and participated in a clinical validation study (n = 254); and (2) a clinical study of patients' seeking treatment for OAB symptoms (baseline assessment) (n = 736). Item and exploratory factor analysis were performed to assess the subscale structure of the questionnaire. Psychometric evaluation was conducted to assess reliability and validity.
RESULTS: Seventy-four percent of the sample were women with mean age of 58.5. Participants with continent and incontinent symptoms reported significantly greater symptom bother and HRQL impact than normal participants. Significant differences were present among all patient groups in all OAB-q subscales (p < 0.0001) except sleep where the impact of continent and incontinent OAB was similar, but significantly worse than normal participants (p < 0.0001). Internal consistency was high with the subscale Cronbach alpha-values ranging from 0.86 to 0.94.
CONCLUSION: The OAB-q is a reliable and valid instrument that discriminates between normal and clinically diagnosed continent and incontinent OAB participants. The OAB-q demonstrates that both continent and incontinent OAB symptoms cause significant symptom bother and have a negative impact on HRQL.