Chinese health literacy scale for tuberculosis patients: a study on development and psychometric testing

BACKGROUND: The role of health literacy on tuberculosis patients has not been evaluated in China, in part because few special health literacy measurements exist. METHODS: A three-step design process was used: (1) Scale construction: Based on the model of revised Bloom’s taxonomy, the item-pool was drafted from a literature review, focus group discussion, and in-depth interviews. In addition, a Delphi survey was used in order to select items for inclusion in the scales; (2) Pilot study: Acceptability and clarity were tested with 60 tuberculosis patients; and (3) Psychometric testing: Validity analysis includes content validity, construct validity, and discriminative validity. The Cronbach’s alpha coefficient, split-half reliability, and test-retest method were used to assess reliability. Finally, a receiver operating characteristic analysis was conducted to generate a cut-off point. RESULTS: The final scale had 29 items with four domains. The item level Content Validity Index ranged from 0.70 to 1.0, and the scale level Content Validity Index was 0.95. The mean score among the lowest 27% group was significantly lower than that those of the highest 27% group (p < 0.01), which supports adequate discriminant validity. Explanatory factor analysis produced a clear four-factor construct, explaining 47.254% of the total variance. Factor 1 and Factor 2 were consistent with read and memorize TB-related words; Factor 3 was associated with understand the meaning of the health education leaflets and examine if TB patients can apply the correct approach to correct context; Factor 4 was related to the ability of TB patient to calculate and identify what unspecified assumptions are included in known conditions. The confirmatory factory analysis results confirmed that a four-factor model was an acceptable fit to the data, with a goodness-of-fit index = 0.930, adjusted goodness of fit index = 0.970, root mean square error of approximation = 0.069, and χ2/df = 2.153. The scale had good internal consistency and test-retest reliability. Additionally, the receiver operating characteristic analysis indicated that the cut-off point for the instrument was set at 45 and 35. CONCLUSIONS: The Chinese Health Literacy scale for Tuberculosis has good reliability and validity, and it could be used for measuring the health literacy of Chinese patients with tuberculosis.