Validation of the Chinese version of the insulin treatment appraisal scale

To test the reliability and validity of the Chinese version of the Insulin Treatment Appraisal Scale (ITAS) questionnaire in patients with type 2 diabetes mellitus (T2DM).

A total of 200 patients with T2DM were consecutively recruited from the outpatient clinic in Taiwan. The World Health Organization guideline was followed to translate the questionnaire. The internal consistency was assessed by Cronbach's α coefficient and item-total correlations. The construct validity was evaluated by using confirmatory factor analysis, convergent validity, and discriminate validity.

The Cronbach's α coefficient for estimates of internal consistency of the total scale was 0.72, and ranged from 0.76 to 0.77 for the subscales. A value of ≥0.40 was considered being substantial. The item-total correlation values were 14 out of 20 items having substantial correlations (4 out of 4 items on the positive appraisal scale and 10 out of 16 items on the negative appraisal scale). The confirmatory factor analysis confirmed both positive and negative factors with total explained variance 33.9% (12.2% for positive subscale and 21.7% for negative subscale). The success rate, calculated from the item-total correlation values, was 70% for the convergent validity (100% for positive subscale and 63% for negative subscale) and 90% for discriminate validity (100% for positive subscale and 88% for negative subscale), respectively. Both the ceiling effect and floor effect were 0%.

The Chinese version of the ITAS questionnaire is a valid and reliable instrument for measuring the perceptions of insulin injection in patients with T2DM.