ABSTRACT
INTRODUCTION: Reliable quality of life (QoL) measures and utility values are needed for patients with type 2 diabetes mellitus (T2DM) with a variety of comorbid conditions to help facilitate cost-effectiveness modeling. This study aimed to evaluate the Diabetes Treatment-Related Quality of Life (DTR-QOL) and EuroQol 5-dimension 5-level (EQ-5D-5L) questionnaires in patients with T2DM with and without diabetes complications and comorbidities in Japan. METHODS: This was an observational survey study involving 1000 patients with T2DM, at least 20 years old, receiving treatment at Nara University Hospital or Takamura Internal Medicine Clinic in Japan. Patients completed the DTR-QOL and EQ-5D-5L questionnaires and clinicians completed an accompanying case report form. The DTR-QOL and EQ-5D-5L are scored on a scale of 0-100 and 0-1, with 100 and 1 representing the best possible scores, respectively. RESULTS: Out of 1000 recruited patients, 978 were included in the final analysis. Patients reported an average EQ-5D-5L value of 0.92 ± 0.11. Utility values corresponded to the degree of severity of health conditions while few differences were observed when stratified by the HbA1c 7% threshold, age, or BMI level, nor did the values correspond to the degree of clinical risk factors. Patients reported an average total DTR-QOL score of 79.26 ± 13.26. The DTR-QOL was sensitive to detect differences in patients with T2DM with a variety of complications and comorbidities, risk factors, and treatments. CONCLUSION: This is the largest study to report QOL values for patients with diabetes in Japan and the first to include a variety of comorbid diabetic conditions. These findings may be useful for cost-effectiveness modeling of patients with T2DM in Japan.
ABSTRACT
OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
