Development of a Brief Korean Version Quality of Life Questionnaire for Incontinence: Combining the Incontinence Quality of Life and Incontinence Impact Questionnaire for Korean Women With Urinary Incontinence

Background: Urinary incontinence (UI) is a prevalent condition that thereby reducing quality of life (QOL) in adult women. Therefore, it is important to assess the impact of UI on daily functioning, social participation, and sexual health. The Incontinence Quality of Life (I-QOL) and the Incontinence Impact Questionnaire (IIQ) are the most widely used assessment tools. The I-QOL focuses on emotional impacts, whereas the IIQ targets activity-related limitations. Using both instruments could provide a more comprehensive assessment; however, this approach increases administration time and introduces redundancy. Objects: This study aimed to develop a concise questionnaire to assess the QOL in patients with UI by merging the Korean version I-QOL and IIQ through Rasch analysis. Methods: A total of 250 women aged 40–69 who had experienced UI were recruited. The combined responses from the 52 items of a questionnaire integrating I-QOL and IIQ were analyzed using Rasch analysis to evaluate item difficulty and separation reliability. Misfit items were excluded and the remaining items were converted into logit values to determine the order of item difficulty. The separation reliability was evaluated using person and item separation indices. Results: By analyzing item difficulty, redundant items with overlapping levels were excluded while retaining the most significant ones, resulting in a final selection of 10 items. Upon reanalysis of these 10 items, the person separation index decreased from 4.96 to 2.47, and the person reliability index decreased from 0.96 to 0.86. However, the item separation index remained high at 7.29 and 7.59, and item reliability index remained at 0.98. Conclusion: The brief questionnaire maintained high reliability and demonstrated the potential for streamlined clinical assessment. The brief instrument offers a reliable and efficient tool for clinical assessment, enhancing the feasibility of evaluating the severity, type, and impact of UI on patients’ QOL.