This study’s aim was to estimate the impact of stress and urgency urinary incontinence (UI) on the quality of life (QOL), and to determine whether the impact differs according to UI severity. Data from the General Longitudinal Overactive Bladder Evaluation-UI study in women was used. Stress and urgency UI symptom severity scores ranged from 0 to 8. Logistic regression to test the relation among different severity levels of stress and urgency UI, and their interaction with the Incontinence Impact Questionnaire (IIQ-7) were used. This was categorized according to percentage ranges as 0-40% (reference), 41-80%, and 81-100%. Both stress and urgency UI had a significant association with IIQ-7. Higher scores had higher odds ratios (ORs). The OR for urgency vs stress UI was greater at the same severity level. For instance, comparing IIQ-7 quintiles (0-40% vs 41-80%), the OR for an association with an urgency UI score of 5-6 was 5.27 (95% CI = 3.78-7.33) vs 2.76 (95% CI = 2.07-3.68) for a stress UI score of 5-6. Both UI subtypes were more strongly associated to the upper (81-100%) than the to the lower (41-80%) quintiles. There was a strong positive urgency UI and stress UI interaction with the upper (i.e., 81-100%) but not the two next lower (41-80%) quintiles.
The impact of UI subtypes on QOL varies according to the score of IIQ-7, stress and urgency UI, and their interaction. Urgency vs stress UI has a more powerful impact. The effect is greatest for high IIQ-7 scores with a significant share mediated by the interaction of the two UI subtypes.