The revalidation of the diabetes treatment-related quality-of-life (DTR-QOL) questionnaire in Japan

The objectives of this study were to develop a conceptual framework for the diabetes treatment-related quality of life (DTR-QOL) and validate the new structure of the DTR-QOL.

This study was conducted in two stages. First, items were collated into similar concepts to develop a new conceptual framework for the DTR-QOL. Next, psychometric analyses were conducted. Analyses included a distribution of responses (and domains) with a focus on floor/ceiling effects, item convergent/discriminant validity, internal consistency reliability (where possible), clinical validity, known-group analysis, and concurrent validity with the Diabetes Treatment Satisfaction Questionnaire and SF-8. Known groups were evaluated using “Glycemic control in the last month”, “Concerned with weight gain in the last month”, “Current health status”, and “Degree of communication with clinician”. To evaluate the reliability of each scale, test–retest were assessed.

The DTR-QOL items were reconstructed into seven domains based on similar concepts: usual activities, pain/discomfort, anxiety/depression, satisfaction, positive feelings, negative feelings, and feeling troubled. Although there were ceiling effects on most items, when patients reported having a hypoglycemic event in the last month, score distributions found fewer ceiling effects indicating that items are able to respond to clinical changes. Internal consistency reliability was met for all scales except satisfaction (α = 0.69) and pain/discomfort (α = 0.66). Clinical validity, known groups, and concurrent validity were met. Test–retest met acceptable levels for all scales except positive feelings.

The restructuring of the DTR-QOL resulted in an acceptable measure with domains that are easily interpreted and allow physicians to better measure more specific impacts on their patients.