A health related quality of life measure for use in patients with urge urinary incontinence: a validation study

Abstract

Objective: Urge incontinence has substantial impact on health related quality of life (HRQOL). The purpose of this research was to test the psychometric properties of the Urge-Incontinence Impact Questionnaire (U-IIQ) and Urge-Urinary Distress Inventory (U-UDI).

Methods: The U-IIQ and the U-UDI were incorporated in a single arm study of an investigational once-a-day formulation of oxybutynin (Ditropan XL) for urge incontinence. The U-IIQ contains 7 scales scored separately: Travel, Activities, Physical activities, Feelings, Relationships, Sexual function and Nighttime bladder control. We also calculated a single index score. The U-UDI contains 9 items summarized in a single score that measures the extent to which incontinence symptoms bother patients and an urge symptoms summary score. Patients completed the questions at: start of baseline week, end of baseline week, week 4 and week 12 (final dose).

Results: The questions were completed by the 257 patients enrolled in the study (91% female, mean age = 60 years). All item responses showed good variability. Internal-consistency reliability was very good (Cronbach's alpha = 0.82-0.96). Test-retest reliability was good for all scales ([ICC] = 0.68-0.83). Discriminant validity was noted for all scales for patients with and without frequent incontinence (p < or = 0.006 all scales). All scales demonstrated responsiveness to change over time (Guyatt's statistic = magnitude of -1.04 - magnitude of -1.71).

Conclusions: Psychometric testing indicated that the scales measured distinct and relevant domains of HRQOL for patients with urge incontinence, and that these two instruments are reliable, valid, and responsive to change in this condition.