Design and Psychometrics of Diabetes Knowledge Questionnaire

Background: Due to the important role played by knowledge in controlling and managing diabetes in most educational interventions, the assessment of the individuals’ levels of knowledge is regarded as a key variable when planning the given interventions. Objectives: This study aimed to design and evaluate the psychometric properties of the Diabetic Knowledge Questionnaire for Iranian diabetic patients. Methods: This cross-sectional study was conducted from March 2020 to May 2021 in Yazd, to examine 400 type 2 diabetes mellitus (T2DM) by adopting the simple random sampling method. Exploratory factor analysis was carried out to evaluate the validity, and 2 methods of test-retest and internal consistency were used to evaluate the reliability. Data were analyzed using SPSS 20 and Amos 21 software. Results: The questionnaire’s items were classified into 6 factors based on factor analysis method; that is, a total of 27 questions with the dimensions of general, hypoglycemia, complications, nutrition, physical activity, and insulin were included. Questions 1 to 24 were allocated to patients with oral therapy, and questions 25 to 27 were allocated to patients under insulin therapy. These factors altogether accounted for 78% of the total variance. The internal correlation coefficient (ICC) for the knowledge questionnaire as a whole was 0.85, which demonstrated an acceptable level of reliability. Also, Pearson correlation coefficient of reliability between test times (test-retest) was found to be 0.92. Conclusions: The instrument was a valid scale designed to assess the awareness of patients with T2DM about various aspects of the disease. However, it was suggested that further studies should be conducted to investigated the patients with type 1 diabetes mellitus (T1DM) as well as patients with different age groups and education levels.