Objective: Compression therapy with the use of graduated compression stockings (GCSs) is a common treatment strategy for chronic venous disease (CVD). However, there is no uniform and objective standard to assess adherence to the use of GCSs. The aim of this study is to develop and validate a GCS Compliance Scale (GCSAS) to fill gaps in internationally recognized comprehensive scales and provide a useful tool for future research.
Methods: The items included in the GCSAS were based on a review of the literature and open-ended interviews with experts, who screened the initial items using an item-level content validity index. Then, pilot tests were conducted three times with 50 participants. After exclusion of redundant and cross-loading items by exploratory factor analysis, 290 subjects were recruited to evaluate the reliability and validity of the proposed GCSAS. Analyses included internal consistency, test-retest reliability, split-half reliability, construct validity, criterion validity, convergent validity, and discriminant validity.
Results: The final GCSAS consisted of 17 items and 5 dimensions. The results of the exploratory factor analysis indicated that the variances of each factor explained were 22.03%, 14.85%, 14.74%, 14.16%, and 13.35%, and all 5 factors explained 79.13% of the variance among the 17 items. The factor loadings of all items were >0.7. Confirmatory factor analysis indicated that the indices were adequate. A significant positive correlation was found between the GCSAS and the Venous Insufficiency Epidemiological and Economic Study - Quality of Life questionnaire scores (r = 0.76, p < 0.001). The Cronbach's alpha coefficient was 0.90, test-retest reliability was 0.81, and split-half reliability was 0.92.
Conclusions: The GCSAS showed good validity and reliability to assess compliance with the use of GCSs among patients with CVD.
Keywords: Chronic venous disease; adherence; graduated compression stockings; reliability; scale; validity.