Psychometric Evaluation of the Brief Illness Perception Questionnaire among Iraqi Patients with Type II Diabetes

Abstract

Background: The Brief Illness Perception Questionnaire (B-IPQ) is one of the most widely used measures of emotional and cognitive representations of illness. The B-IPQ has been translated and adapted into many languages. However, the scale has not been translated into Iraqi Arabic in patients with type II diabetes. The main purpose of the present study was to investigate psychometric properties of the B-IPQ among Iraqi patients with type II diabetes. Methods: In this quantitative study, the Arabic Version of the B-IPQ was given to 192 Iraqi patients with type II diabetes. The participants were randomly selected from 5 hospitals and a diabetes society in Baghdad, Iraq. The participants included individuals diagnosed at least 1 year before this research. Using WINSTEPS computer program, the Rating Scale Model ‎(RSM) was employed as a polytomous extension of the Rasch model (RM) to evaluate the scale in terms of unidimensionality, local independence, item statistics, and rating structures. Results: The results indicated that the values of infit and oufit mean square (MNSQ) are within the ideal range of 0.60 and 1.40, suggesting that the items of the scale fit to the RM. The data was found to be unidimensional because the first factor explains 5.5% of the unexplained variance with an eigenvalue of 1.5 (< 2). The results also showed that items are locally independent, and both persons and items have high Rasch separation reliability indices. More importantly, the response options or categories of the scale work optimally because with the increase in category values, observed averages also increased. Conclusion: The overall findings showed that the Arabic version of the B-IPQ is a valid and reliable instrument and can be employed to assess illness perceptions among Iraqi patients with type II diabetes.