Adaptation and validation of quality of life instrument Diabetes 39 for Mexican patients with type 2 diabetes mellitus

OBJECTIVE: To adapt and validate the Spanish language version of the Diabetes 39 instrument, which measures quality of life,for Mexican patients with type 2 diabetes mellitus (DM-2). MATERIALS AND METHODS: The Spanish language version of the instrument was adapted to make it more comprehensible to Mexican patients. In a cross-sectional survey, the instrument was administered on two different days to 260 patients with type DM-2. Glycated hemoglobin (HbAic), total cholesterol, triglycerides, blood pressure, body mass index and waist/hip ratio were measured. Information about age, sex, time since diagnosis of diabetes, diabetes related complications and comorbidity was obtained. RESULTS: A total of 249 subjects completed the study, 62.7% of which were women. Cronbach's alpha coefficient was > or = 0.80 for the domains and 0.95 for the total score.The test-retest consistency for the total score was r = 0.82, p = 0.01. The median of the total score was 29 (on a scale of 0-100), which was considered the cutoff value for defining "better" (<29) and "worse" > or =29) quality of life.A worse quality of life was associated with diabetes related complications > or =1 (OR = 1.73; IC 95% 1.05-3.06); total cholesterol >240 mg/dL (OR = 4.43; IC 95% 1.23-16.26); comorbidity > or =2 diseases (OR = 2.36; IC 95% 1.31-4.28); diabetes longer than 10 years (OR = 2.19; IC 95% 1.2-3.78), and HbA(IC) >8% (OR = 1.81; IC 95% 1.09-2.99). The last three were identified as predictor variables for worse quality of life by logistic regression (p < 0.05). CONCLUSIONS: The adapted Spanish language version of Diabetes 39 is a reliable and valid instrument for measuring the quality of life of Mexican patients with DM-2.