As a basic psychological need, the level of perceived competence could expedite the achievement of diabetes self-management goals. Because of a lack of a specific data collection tool to measure the level of self-competence among Persian-speaking patients with diabetes, this study was conducted for (1) cross-cultural adaptation and (2) psychometric assessment of the Persian version of the Perceived Competence Scale for Diabetes (PCSD-P). Standard translation/back-translation procedure was carried out to prepare a preliminary draft of the PCSD-P. Content and face validities of the early draft were checked by an expert panel including 15 scholars in the field of health education and promotion as well as nursing education with experience of working and research on diabetes. The final drafted questionnaire was completed by 177 randomly selected patients with type 2 diabetes. On the basis of the collected data, the structural validity of the contrived version was appraised using exploratory and confirmatory factor analysis (EFA, CFA). Cronbach's alpha and intraclass correlation (ICC) coefficients were used to check the scale's reliability and internal consistency. The estimated measures of content validity index (CVI = 0.95) and content validity ratio (CVR = 0.8) were within the acceptable recommended range. The EFA analysis results demonstrated a single factor solution according to the items' loadings for the corresponding component. The model fit indices, that is, root mean square error approximation (RMSEA = 0.000), comparative fit index (CFI = 1), Tucker-Lewis index (TLI = 1), incremental fit index (IFI = 1), normed fit index (NFI = 0.999), and relative fit index (RFI = 0.995), confirmed the consistency of the hypothesized one-factor solution. The values of the internal consistency and reliability coefficients were also in the vicinity of an acceptable range (α = 0.892, ICC = 0.886, P = 0.001). The study findings revealed good internal validity and applicability of the PCSD-P to measure the degree of self-competence among Persian-speaking type 2 diabetes patients to manage the chronic disease. Owing to unrepresentativeness of the study sample, future cross-cultural tests of PCSD-P are recommended on diverse and broader Persian-speaking populations.
Keywords: diabetes mellitus; questionnaire design; self-care; self-perception; validation.