Objective: To estimate the criterion validity of a self-administered questionnaire on urinary incontinence (UI) using a clinical stress UI test as reference.
Material and methods: A total of 4710 women aged 20-59 years randomly selected from the municipalities of Aarhus and Randers (Denmark) participated in a population survey on UI. A sub-sample of 96 women stratified by the duration and frequency of UI answered an assisted, self-administered questionnaire concerning UI during the preceding 6 months. Subsequently, a clinical stress UI test was performed with the researchers being blinded with regard to the questionnaire information.
Results: Based on the clinical stress test and questionnaire, 22 (22.7%) and 21 women (21.6%) had stress UI, respectively. UI occurring in more than drops and UI lasting for > 4 weeks were found to be adequate predictors of UI (odds ratio 8.9 and 4.6; p < 0.001 and p < 0.05). Regarding all forms of UI, the agreement between the stress UI test result and the questionnaire data ranged from 51.0% to 77.1%. The probability of finding a positive stress UI test was 62% among women who answered that UI had lasted for > 4 weeks and occurred in more than drops, compared to 22.9% in the total study group. The sensitivity and specificity of the stress UI test among women in whom UI lasted for > 4 weeks and occurred in more than drops were 22.7% and 95.9%, respectively.
Conclusions: These findings suggest that there is a greater probability of finding severe UI if the women have experienced it in more than drops and it has lasted for > 4 weeks and it is therefore necessary to estimate the degree of incontinence further by means of a stress UI test. In contrast, women who experienced UI in less than drops and for a duration of < 4 weeks only suffered from a very mild degree of UI.