Psychometric validation of the 14 items chronic venous insufficiency quality of life questionnaire (CIVIQ-14): confirmatory factor analysis

Abstract

Objectives: The study aim was to confirm the factorial structure of the short (14 item) version of the ChronIc Venous Insufficiency quality of life Questionnaire (CIVIQ-14) using the Vein Consult Program (VCP) results. Methods: The international VCP study sought to evaluate the impact of chronic venous disease (CVD) on health care costs and quality of life (QoL). The factorial structure of the CIVIQ-14 was evaluated using two methods: exploratory factor analysis (EFA) to calculate the probabilities of items and dimensions remaining stable and to study the dimensionality of the scale using explained variance criteria, followed by confirmatory factor analysis (CFA) to confirm the original three dimensional structure and investigate alternative models that may have arisen from the dimensionality analysis. We also used the VCP results to evaluate the psychometric properties of the questionnaire and conducted subgroup analyses on countries with validated translations. Results: A total of 47,149 questionnaires from 17 countries were available in the VCP. EFA revealed both items and dimensions as 100% stable. Dimensionality analysis showed that a two factor approach could be considered. CFA revealed the CIVIQ-14 three dimensional structure to be acceptable while rejecting the two dimensional model. Psychometric analysis confirmed the construct validity, internal consistency, and known groups validity of the CIVIQ-14. The results of subgroup analyses were consistent with those of the primary analysis. Conclusions: CFA of VCP data supported the factorial structure of the CIVIQ-14. The analysis corroborates the wide use of CIVIQ-14 as a valid instrument for reporting QoL in CVD patients.