Assessment of the relative performance of the EQ-5D-3L, ICIQ UI SF and POP-SS using data from the OPAL trial

Conducting economic evaluations alongside randomised controlled trials (RCTs) is an efficient way to collect cost-effectiveness data. Generic preference-based measures, such as EQ-5D, are often used alongside clinical data measures in RCTs. However, in the case of female urinary incontinence (UI), evidence of the relative performance of EQ-5D with condition-specific measures such as the International Consultation on Incontinence Questionnaire Urinary Incontinence Short Form (ICIQ-UI SF), measuring severity of UI, and Pelvic Organ Prolapse Symptom Score (POP-SS), measuring severity of prolapse symptoms, is limited. This study employed secondary analysis of outcome measures data collected during the Optimal Pelvic floor muscle training for Adherence Long-term (OPAL) RCT, which compared biofeedback-mediated pelvic floor muscle training to basic pelvic floor muscle training for women with UI. The relative performance of EQ-5D-3L and ICIQ-UI SF, and EQ-5D-3L and POP-SS was assessed for concurrent validity and known-groups validity. Data for 577 women (mean age 48) were available for EQ-5D-3L/ICIQ-UI SF, and 555 women (mean age 47) for EQ-5D-3L/POP-SS. Overall, EQ-5D-3L exhibited very weak association with the ICIQ-UI SF total score, or any subscale. EQ-5D-3L and POP-SS were found to be weakly correlated. EQ-5D-3L was able to distinguish between groups with known differences in severity of UI and also between types of UI. These findings provide useful information to guide researchers in selecting appropriate outcome measures for use in future clinical trials.