Development and Validation of the Chinese Insulin Medication Literacy Scale (Ch-InMLS) for Patients with Diabetes Mellitus

Objective: The aim of this study was to develop a simplified insulin medication literacy scale for patients with diabetes mellitus and evaluate its psychometric properties. Methods: We developed an initial scale based on the framework of knowledge-attitude-practice model (KAP) with skills added, and the items were developed from literature review and insulin related guidelines, semi-structured interviews, cognitive interviews. After two rounds of expert consultation and pilot survey, a final version of the scale was developed. A cross-sectional survey was conducted with 553 patients with diabetes mellitus in Zhengzhou for the psychometric evaluation. In the construct validity, the number of participants was 262 for exploratory factor analysis and 291 for confirmatory factor analysis. In the reliability, internal consistency reliability and split-half reliability were evaluated using Cronbach’s alpha coefficients. Results: The final scale consists of 36 items with 4 dimensions, including knowledge, attitude, practice, skill. EFA suggested four factors explaining 67.556% of the total variance (Kaiser–Meyer-Olkin test = 0.944, Bartlett’s test χ2 = 7384.296, P < 0.001). The results of confirmatory factor analysis showed that the model fit the data adequately. The Cronbach’s a coefficient was 0.849 for the overall scale and ranged from 0.744 to 0.783 for domains. The Spearman-Brown split-half reliability coefficient was 0.893 for the total scale and ranged from 0.793 to 0.872 for domains. The test-retest reliability coefficient of the total scale was 0.968 and ranged from 0.880 to 0.959 for domains. Conclusions: The scale has acceptable content validity, construct validity, and good reliability. It can be used to evaluate the level of insulin medication literacy of patients with diabetes mellitus in China.