Background: The factorial instability of the CIVIQ-20 social dimension in different populations has necessitated the development of a new stable questionnaire to interpret results from international studies.
Objective: Construction of a stable and psychometrically validated questionnaire from CIVIQ-20.
Methods and major findings: A prospective, international study was used to construct a stable CIVIQ scale and to validate its psychometric properties. An iterative process was implemented to eliminate the more unstable items (six), and the social and physical dimensions were combined. The resulting instrument comprised 14 items, split into three dimensions (pain, physical, and psychological), and was named CIVIQ-14. The stability of the CIVIQ-14 factorial structure was confirmed in Polish, Czech, Spanish, and French populations using principal component analysis and multitrait/multimethod analysis. Psychometric assessment demonstrated that CIVIQ-14 was reliable (intra-class coefficient >0.8; weighted kappa >0.8), valid (correlation coefficients between dimension scores and clinical severity scores between 0.3 and 0.6), and sensitive (effect sizes >0.6 for psychological dimension; >0.8 for the other dimensions).
Conclusion: CIVIQ-14 is a reliable, valid, and sensitive instrument applicable to international studies of patients with chronic venous disease.