Developing a quality of life measure for Chinese patients with diabetes.

The objective of this study was to develop a Chinese version of the Diabetes Quality of Life measure (DQOL), appropriate for elderly Chinese immigrants with Type 2 diabetes, and evaluate its reliability and validity through psychometric testing. Using an established diabetes quality of life measure, we employed focus groups to modify the instrument to be appropriate for an elderly Chinese population. The revised version was forward translated and back translated by four individuals independently. A review committee consensus determined the final version, which was pre-tested on five lay people to assess the equivalence of meaning. Elderly Chinese patients with Type 2 diabetes (n = 70) attending either an endocrinology or family practice clinic near Toronto were recruited to complete the Chinese version of the DQOL. Reliability of the instrument was assessed by evaluating internal consistency, item-internal consistency and test-retest reliability. Divergent validity was assessed to show that the instrument could detect worsening quality of life associated with diabetic complications. The Chinese version of the DQOL consists of 42 items and three scales including satisfaction, impact and diabetes-related worry. The DQOL and its three scales had high degrees of internal consistency (Cronbach's alpha = 0.76-0.92) and excellent test-retest reliability (Pearson correlation = 0.94-0.99). All items had high correlation with their hypothesized scale with the exception of three items. Divergent validity of the instrument was demonstrated. This study provides evidence for the reliability and validity of this Chinese version of the DQOL measure for an elderly Chinese population with Type 2 diabetes. This instrument may be used in future studies to better understand the quality of life of the Chinese population with diabetes.