International Psychometric Validation of the Chronic Venous Disease Quality of Life Questionnaire (CIVIQ-20)

Launois R, Mansilha A, Jantet G. Eur J Vasc Endovasc Surg. 2010;40:783-789

Reviewed by
Francisco LOZANO, Salamanca, Spain

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The 20-item self-reported quality of life questionnaire scale called Chronic Venous disease quality of life Questionnaire-20 (CIVIQ-20) was created and validated in France in 1996,¹ as a sensitive instrument to capture the key dimensions of quality of life (QoL) specifically impaired by chronic venous disease (CVD). In the original French version, the five conditions required for validation (relevance, acceptability, reliability, construct validity, and sensitivity) were met. Four dimensions of the CIVIQ-20 were identified: physical (4 items), psychological (9 items), social (3 items), and pain (4 items).

Because the cross-cultural equivalence of instruments is recognized as a major issue in the assessment of QoL in large international studies, the purpose of this article was to review the results of the psychometric validation of the CIVIQ-20 in the 18 countries of the Reflux assEssment and quaLity of lIfe improvEment with micronized Flavonoids (RELIEF) study.²

CIVIQ-20 has been administered to patients from 18 countries in South America, Central, Southern and Eastern Europe, North Africa, North, South and East Asia, so linguistic validation was necessary. The linguistic validation was done in two steps: first, confirmation of the cultural relevance of the questionnaire’s content; second, the translation process. The linguistic validation of the translation of CIVIQ-20 into 13 languages (see Table I) using the forward-backward process will be the subject of another publication.

Table I – Summary of the available linguistic versions of CIVIQ-20 (click to enlarge the figure)

RESULTS of the psychometric validation: In the 3956 patients included in the analysis, CIVIQ-20 showed good content validity and reliability (above 0.80). A content validity index over 0.80 suggests that the items are appropriate, and a high index of reliability verifies that the instrument produces similar results in measuring the same phenomenon on a number of occasions.

The discriminating power of items was also good in patients with known differences in symptom scores and CEAP classes at baseline, implying that the scale is able to discriminate between severity states of chronic venous disease. CIVIQ-20 was highly sensitive to changes in the quality of life of patients clinically improved after drug treatment, showing its ability to reflect changes in the clinical variables that occur during treatment.

A key concern in extending the use of an instrument that has been validated in one country to other sociocultural groups is whether the instrument designed to measure the relevant constructs is cross-culturally stable. In today’s world of ever-increasing globalization, investigators willing to assess the impact of a disease or a treatment on patients’ daily lives are often interested in comparing people from different countries and different sociocultural groups in terms of a variety of psychosocial variables. A necessary assumption when comparing populations from different countries using a multi-item instrument such as CIVIQ-20 is that the items quantifying the construct function in the same way across samples from different cultures. This property of an instrument is referred to as factorial stability.

CIVIQ-20 is the only specific scale for CVD to have used item and factor analysis to demonstrate to what extent the items are convergent with their dimension. Factor analysis identified physical, psychological, and pain factors as important, but revealed instability of the social factor. Given the complexity of translating scale items into different languages, the absence of complete stability is not surprising.  Numerous specific scales for chronic venous disease have been developed in the last 20 years. This may reflect the difficulty of finding an instrument applicable to the wider spectrum of CVD. It is true that in the quality of life field, it cannot be claimed that any of these scales have been truly validated or have shown factorial stability.

Overall, in its current form, the CIVIQ-20 scale offers good, albeit not perfect, metrological properties and may use the global index for the assessment of the quality of life in CVD which is easier to handle in multinational studies than the indexes per dimension.

References:
1. Launois R, Reboul-Marty J, Henry B. Construction and validation of a quality of life questionnaire in chronic lower limb venous insufficiency (CIVIQ). Qual Life Res. 1996;5:539-554.
2. Jantet G. Chronic venous insufficiency: worldwide results of the RELIEF study. Reflux assEssment and quaLity of lIfe improvEment with micronized Flavonoids. Angiology. 2002;53:245-256.