A validated patient reported measure of urinary urgency severity in overactive bladder for use in clinical trials

PURPOSE: Overactive bladder (OAB) is a syndrome consisting of urinary urgency with or without urge incontinence, usually with increased urinary frequency and nocturia. In response to current limitations in OAB clinical research a new patient reported measure of urgency severity associated with OAB has been developed, namely the Indevus Urgency Severity Scale (IUSS). We report the measurement properties of the IUSS. MATERIALS AND METHODS: Validation study data were collected alongside a phase III clinical trial of 20 mg trospium chloride twice daily vs placebo in patients with OAB associated with urge incontinence. We evaluated IUSS item variability, known group, content, criterion and construct validity, test-retest reliability, responsiveness and respondent burden. RESULTS: A total of 658 patients were evaluated at baseline and 579 were reevaluated at week 12. IUSS demonstrated good item variability. Greater urgency severity was associated with increased symptom bother and worse health related quality of life, as measured by the OAB QOL questionnaire. IUSS had a significant positive association with essential clinical and quality of life outcomes, demonstrating content validity. IUSS was highly responsive to a decrease in the average number of patient toilet voids per 24 hours to 7 or fewer toilet voids and average urge incontinence episodes per 24 hours to zero. It discriminated between patients who had above and below the median number of toilet voids and urge incontinence episodes per 24 hours. IUSS also had good test-retest reliability and content validity, and it created minimal respondent burden. CONCLUSIONS: IUSS is a validated patient reported measure of urgency severity for collecting event specific information in the context of a clinical trial.