Translation and application of condition-specific health-related quality of life questionnaires for women with pelvic organ prolapse and pelvic floor dysfunction in the Norwegian context

Author: Catherine Teig

Teig, Catherine, 2019 Translation and application of condition-specific health-related quality of life questionnaires for women with pelvic organ prolapse and pelvic floor dysfunction in the Norwegian context, Flinders University, College of Medicine and Public Health

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Abstract

Introduction: The goal was to translate to Norwegian, and validate, short versions of the Pelvic Floor Distress Inventory (PFDI-20) and Pelvic Floor Impact Questionnaire (PFIQ-7) using a sample of women with symptomatic POP and pelvic floor dysfunction. For translation and cross-cultural adaptation of the PFDI-20 and PFIQ-7, a new methodology was developed using the Delphi method approach with a bilingual expert panel.

Method: The PFDI-20 and PFIQ-7 were first translated from English into Norwegian using a multistep translation and cultural adaptation method. This new method combined the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group guidelines, the Delphi method, and an expert panel review. It involved two independent forward and back-translations, with the addition of the Delphi method (anonymous voting, controlled feedback, statistical group response) to establish consensus on translated items among a bilingual pelvic floor expert panel. The translated instruments were then pilot tested through face-to-face semi-structured interviews with 20 women with symptomatic POP.

A total of 205 Norwegian women with symptomatic POP (with or without urinary or bowel dysfunction) completed the questionnaires; 50 completed them again after 1 to 3 weeks, and 76 completed them again 6 months after surgery. The median age of the sample was 61 years (range, 27–82 years). Reliability, validity, and responsiveness were evaluated. Additionally, interpretability, smallest detectable change, standard error of measurement, floor and ceiling effects, and percentage of missing items were reported.

Results: This new translation and cultural adaptation method produced a Norwegian PFDI-20 and PFIQ-7 Intermediate Version 2.0 that demonstrated semantic, conceptual, idiomatic, and experiential equivalence with the original versions. This Intermediate Version 2.0 was then ready for pilot testing. During the pilot test minor discrepancies were identified and amended to produce a Norwegian PFDI-20 and PFIQ-7 Intermediate Version 3.0 that was ready for validation.

Cronbach’s alpha ranged from 0.66 to 0.93, and intraclass correlation coefficients ranged from 0.85 to 0.94. Both construct validity and responsiveness were noted to be adequate. Responsiveness was further supported for PFDI-20 with areas under the curve above 0.70. Estimates were lower for PFIQ-7. Smallest detectable change at the individual level constituted 15% to 21% and 17% to 27% for the PFDI-20 and PFIQ-7, respectively. The absolute value for Minimal Important Change for total scores was 48 and 47 for the PFDI-20 and PFIQ-7, respectively. No floor or ceiling effects were evident in the PFDI-20 and PFIQ-7 total score distributions.

Conclusions: Efforts to ensure a good translation and cross-cultural adaptation of the PFDI-20 and PFIQ-7 resulted in the development of a new study methodology, which used the Delphi method with a bilingual expert pelvic floor panel. The controlled feedback approach, the iterative nature and internal logic of the Delphi consensus method appeared to contribute to improving translation results and ensuring good cross-cultural adaptation of the questionnaires.

The translated questionnaires provided adequate reliability, validity and good responsiveness to change. These short versions of the Pelvic Floor Distress Inventory (PFDI-20) and Pelvic Floor Impact Questionnaire (PFIQ-7) are robust measuring instruments that will enable symptom severity and health-related quality of life to be evaluated in the Norwegian context.

Keywords: Translation, Delphi Method, Norwegian, validation, PFDI-20, PFIQ-7, pelvic organ prolapse, pelvic floor dysfunction, PROM, Patient Reported Outcome Measures, questionnaire

Subject: Medicine thesis

Thesis type: Doctor of Philosophy
Completed: 2019
School: College of Medicine and Public Health
Supervisor: Angelita Martini