Normative data and psychometric properties of the quality of life questionnaire for patients with diabetes mellitus

Diabetes mellitus (DM) affectes multiple aspects of life in a diabetic patient. These influences does not take two much attention in the health system. The Persian version of quality of life assessment tools in these patients is not checked. The aim of this study was to examine the normative data and some of the psychometric properties of the Persian version of quality of life questionnaire in patients with diabetes mellitus in an Iranian population. Subjects were DM patients who were referred to health centers of Isfahan city (Iran) in 2007. A total number of 120 diabetic patients were selected through stratified randomized sampling as well as equal number of matched control subjects. A demographic questionnaire, diabetes quality of life (DQOL) and WHO- quality of life (WHO-QOL) tools were administered to both groups. The total mean score of QOL was relatively low in DM patients except for the domains of worries. Using the chronbach’s alpha test, the reliability of the whole questionnaire and its subscales were determined to be 0.89 and 0.51 to 0.84, respectively. Also each question showed an internal positive consistency whit the whole questionnaire except for the 8th question of the effects domain (r= -0.21). The correlation co-efficient of co-administration of the two questionnaires and their subscales were 0.63 0.60, 0.39 and 0.05, respectively. The range of rough scores of the patients and the healthy subjects were 1.37 to 3.97 and 1.18 to 3.37, respectively. The cut-off point was determined to be 2.06 based on the analysis of differentiations. The factor analysis was using the major elements and Varimax Rotation resulted in 6 factors. Our findings showed that the DQOL has proper normative data and psychometric properties in our samples. This questionnaire can be used in confidence by the health centers of Iran.