Development and psychometric evaluation of a diabetes-specific quality-of-life (D-QOL) scale.

Aims: The aims of this study were to develop a diabetes-specific quality-of-life (D-QOL) scale and to determine its psychometric properties.

Methods: An initial pool of items was generated based on a conceptual construct and attributes of health-related quality of life. The items were reviewed by experts, and a pilot test was conducted. A content-validated preliminary D-QOL scale was verified for use with psychometric tests on 402 patients who were recruited from 3 hospitals in Korea. The data were analyzed using exploratory and confirmatory factor analyses, Cronbach's alpha, generalizability coefficients, ANOVA, and Pearson's correlations.

Results: From exploratory analyses, a total of sixteen items clustered four factors were extracted. The four-factor structure was supported by confirmatory factor analysis. Concurrent validity was established with the 36-item Short-Form Health Survey. As hypothesized, the D-QOL scores were worse in severely or moderately depressed patients than in those who were either less depressed or not depressed, implying satisfactory known-groups validity. The reliability of the D-QOL scale was supported by Cronbach's alpha and generalizability coefficients.

Conclusions: The D-QOL scale is a simple and brief scale, the use of which is feasible in practice. It demonstrated excellent psychometric properties, and so may also be used in clinical research.