Assessing the impact of diabetes on quality of life: validation of the Chinese version of the 19-item Audit of Diabetes-Dependent Quality of Life for Taiwan

Abstract

OBJECTIVE: To examine the reliability and validity of the Chinese version of the 19-item Audit of Diabetes-Dependent Quality of Life for Taiwan (ADDQoL-CnTW). METHODS: Linguistic validation procedures for patient-reported outcome measures were used to translate the Taiwan version from the original 19-item UK-English ADDQoL. The psychometric properties of the ADDQoL-CnTW were evaluated in a convenience sample, recruited from outpatient facilities, of 260 patients diagnosed with diabetes mellitus. RESULTS: The forced one-factor solution supported one general 19-item factor with all items loading above 0.43, accounting for 51.5% of the variance, although the results of confirmatory factory analysis did not strictly adhere to a one-factor structure. Using Kaiser's Criterion, exploratory factor analysis identified four sub-dimensions but the pattern of loading also confirmed the presence of a large general factor with 11 of 19 items loading ≥0.4 on the first component, accounting for 49.73% of the variance. Internal consistency for the entire scale was 0.94. Convergent and discriminant validity were suggested by a stronger correlation of average weighted impact (AWI) scores with the overview Diabetes-specific QoL item than with the Present QoL item. The Present QoL item correlated better with the World Health Organization Quality of Life-BREF(TW) dimension scores than the Diabetes-specific QoL scores or the AWI scores. Insulin-treated patients reported significantly more negative AWI scores and Diabetes-specific QoL scores than those treated with tablets and/or diet, demonstrating known-groups validity. CONCLUSIONS: The ADDQoL-CnTW revealed excellent internal consistency reliability, and showed evidence of validity for use in Taiwanese people with diabetes.