Psychometric properties of the Chinese version of the Self-Efficacy for Appropriate Medication Use Scale in patients with stroke

Background: It has been reported that stroke has a higher incidence and mortality rate in the People's Republic of China compared to the global average. These conditions can be managed by proper medication use, but ensuring medication adherence is challenging. Objective: To translate the Self-Efficacy for Appropriate Medication Use Scale into Chinese and test its validity and reliability in patients with stroke. Methods: Instrument performances were measured from January 15, 2015 to April 28, 2015 on a convenience sample of 400 patients with stroke recruited at four neurology departments of the First Affiliated Hospital of Zhengzhou University. Questionnaires included the Chinese versions of the Self-Efficacy for Appropriate Medication Use Scale (C-SEAMS) and the General Self-Efficacy Scale (C-GSE). Construct validity, convergent validity, internal consistency, and test-retest reliability were measured. Results: Item analysis showed that item-to-total correlations were in the range of 0.362-0.672. Exploratory factor analysis revealed two factors (which accounted for 60.862% of total variance), with factor loading ranging from 0.534 to 0.756. Confirmatory factor analysis was performed to support the results, with an acceptable fit (chi(2)=73.716; df=64; P<0.01; goodness-of-fit index=0.902; adjusted goodness-of-fit index =0.897; comparative fit index =0.865; root-mean-square error of approximation =0.058). The convergent validity of the C-SEAMS correlated well with the validated measure of the C-GSE in measuring self-efficacy (r=0.531, P<0.01). Good internal consistency (Cronbach's alpha ranged from 0.826 to 0.915) and test-retest reliability (Pearson's correlation coefficient r=0.642, P<0.01) were found. Conclusion: The C-SEAMS is a brief and psychometrically sound measure for evaluating self-efficacy for medication adherence in the Chinese population with stroke.