Quality of life of women with urinary incontinence: cross-cultural performance of 15 language versions of the I-QOL

Abstract

Urinary incontinence (UI) has substantial and important impacts on health-related quality of life. The purpose of this research is to report the psychometric performance of 15 different language versions of the Incontinence-specific Quality of Life (I-QOL)measure, a patient-reported outcome measure specific to stress, urge and mixed urinary incontinence. The multi-national dataset consisted of data from four clinical trials for stress incontinent females and from two additional population studies, enrolling women with stress, urge and mixed UI. All enrolled patients completed the I-QOL and comparative measures at baseline. The clinical trial populations had multiple administrations up to 12 weeks, and the two population studies included a shorter retest. Country-specific psychometric testing for validity, reliability, and responsiveness followed standardized procedures. Confirmatory factor analyses were performed to assess the I-QOL subscales. The I-QOL measurement model was confirmed as three subscales. Summary and subscale scores for the 15 versions were internally consistent (alpha values = 0.91-0.96) and reproducible (ICC = 0.72-0.97). Using changes in the independent measures of incontinence episode frequency standardized response means were predominantly strong (ranged 0.71-1.05) across 13 versions (out of 15) in association with these measures and effect sizes. These additional language versions of the I-QOL instrument demonstrate psychometric properties similar to the original version. The I-QOL has shown good results in both community studies and clinical trials with varying types and severity of urinary incontinence. It is a reliable and valid measure of HRQOL, suitable for use in a variety of international settings.