Validation of the Pelvic Floor Distress Inventory-20 and the Pelvic Floor Impact Questionnaire-7 in Danish women with pelvic organ prolapse

Objective. To translate the Pelvic Floor Distress Inventory-20 (PFDI-20) and the Pelvic Floor Impact Questionnaire-7 (PFIQ-7) and to evaluate their psychometric properties in Danish women with symptomatic pelvic organ prolapse. Design and setting. Cross-sectional, university hospital setting. Sample. Women with symptomatic pelvic organ prolapse (n = 132). Methods. A panel of gynecologists performed three independent translations, which were combined and psychometrically evaluated through interviews and pretesting. Main outcome measures. Construct, content and convergent validity. Internal consistency and reliability. Sensitivity to change, responsiveness and minimal clinical important difference. Results. After two revisions PFDI-20 demonstrated good construct and content validity but PFIQ-7 showed major ceiling effect and lacked items describing affection of health-related quality of life. Convergent validity was moderate with only single items of PFDI-20 correlating with the pelvic organ prolapse quantification system (POP-Q) and only weak to moderate correlations between PFDI-20 and PFIQ-7 scores. Cronbach's alpha and inter-item-total correlation analysis were satisfactory overall. Intra-class correlation coefficient demonstrated good reliability for all but one subscale (r = 0.701-0.894 p < 0.001). Wilcoxon signed rank test showed significant sensitivity to change. Effect size and standardized response mean was good in pelvic organ prolapse subscales and correlated with the Patient Global Index of Improvement scale (PGI-I). Minimal clinical important difference could not be clearly demonstrated. Conclusion. The Danish version of PFDI-20 is valid while the PFIQ-7 has a major ceiling effect and lacks items about health-related quality of life. The subscales of PFDI-20 and PFIQ-7 demonstrate good internal consistency and reliability. Pelvic organ prolapse subscales show good responsiveness.