Validation of the short forms of the Pelvic Floor Distress Inventory and the Pelvic Floor Impact Questionnaire in Estonian

Abstract

Introduction and hypothesis Pelvic Floor Distress Inventory (PFDI-20) and the Pelvic Floor Impact Questionnaire (PFIQ-7) are reliable instruments for evaluating the quality of life in women with pelvic organ prolapse (POP). They have been translated and validated in many languages. The study was aimed at validating the Estonian translations of the PFDI-20 and PFIQ-7 tools. Methods The questionnaires were translated into Estonian using a multistep translation method. A total of 132 women were enrolled: patients with diagnosed POP (n=57) were allocated to test–retest reliability analyses, and those with no POP signs (n=88) completed the questionnaire only once. The total scores of questionnaires and their subscales of both patient and reference groups were compared. Item response rate, floor and ceiling effects, corrected item–total correlations, internal consistency, and convergent and discriminant validity were analyzed. The study was approved by the Ethics Committee of Human Research of the University Clinic of Tartu, Estonia, and informed consent was obtained from each participant. Results The translated questionnaires demonstrated good internal consistency (Cronbach's α values 0.77–0.93). The item response rate was 99%. Intra-class correlations (ICC) were strong for PFDI-20 and PFIQ-7 and their subscales ranged from 0.86 to 0.96. Construct validity of the tools demonstrated by manyfold higher scores among patients with POP compared with women without POP (p<0.0001). Conclusions The Estonian versions of the PFDI-20 and PFIQ-7 tools are reliable and valid instruments for assessing the quality of life in women with POP.