The purpose of this study was to review articles related to the psychometric properties of the Perceived Stress Scale (PSS). Systematic literature searches of computerized databases were performed to identify articles on psychometric evaluation of the PSS. The search finally identified 19 articles. Internal consistency reliability, factorial validity, and hypothesis validity of the PSS were well reported. However, the test-retest reliability and criterion validity were relatively rarely evaluated. In general, the psychometric properties of the 10-item PSS were found to be superior to those of the 14-item PSS, while those of the 4-item scale fared the worst. The psychometric properties of the PSS have been evaluated empirically mostly using populations of college students or workers. Overall, the PSS is an easy-to-use questionnaire with established acceptable psychometric properties. However, future studies should evaluate these psychometric properties in greater depth, and validate the scale using diverse populations.

Background: The internet is now a major source of health information. With the growth of internet users, eHealth literacy has emerged as a new concept for digital health care. Therefore, health professionals need to consider the eHealth literacy of consumers when providing care utilizing digital health technologies. Objective: This study aimed to identify currently available eHealth literacy instruments and evaluate their measurement properties to provide robust evidence to researchers and clinicians who are selecting an eHealth literacy instrument. Methods: We conducted a systematic review and meta-analysis of self-reported eHealth literacy instruments by applying the updated COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) methodology. Results: This study included 7 instruments from 41 articles describing 57 psychometric studies, as identified in 4 databases (PubMed, CINAHL, Embase, and PsycInfo). No eHealth literacy instrument provided evidence for all measurement properties. The eHealth literacy scale (eHEALS) was originally developed with a single-factor structure under the definition of eHealth literacy before the rise of social media and the mobile web. That instrument was evaluated in 18 different languages and 26 countries, involving diverse populations. However, various other factor structures were exhibited: 7 types of two-factor structures, 3 types of three-factor structures, and 1 bifactor structure. The transactional eHealth literacy instrument (TeHLI) was developed to reflect the broader concept of eHealth literacy and was demonstrated to have a sufficient low-quality and very low-quality evidence for content validity (relevance, comprehensiveness, and comprehensibility) and sufficient high-quality evidence for structural validity and internal consistency; however, that instrument has rarely been evaluated. Conclusions: The eHealth literacy scale was the most frequently investigated instrument. However, it is strongly recommended that the instrument's content be updated to reflect recent advancements in digital health technologies. In addition, the transactional eHealth literacy instrument needs improvements in content validity and further psychometric studies to increase the credibility of its synthesized evidence.

Health literacy has been attracting increasing attention because low health literacy is considered an important predictor of adverse health outcomes in many chronic conditions, including diabetes. However, it is unclear how health literacy is associated with health outcomes. The purpose of this study was to formulate a hypothetical structural equation model linking health literacy to self-efficacy, self-care activities, and health-related quality of life (HRQOL) in patients with type 2 diabetes. A cross-sectional survey design was employed, and 459 patients with type 2 diabetes were recruited from outpatient clinics in two university hospitals. The patients completed a pack of questionnaires. The hypothetical model was tested using structural equation modeling analysis. The values of multiple fit indices indicated that the proposed model provided a good fit to the data. Health literacy exerted not only a direct effect on self-care activities, but also an indirect effect on self-care activities via self-efficacy. However, health literacy exerted only an indirect effect on HRQOL. This structural model was invariant across hemoglobin-A1c-controlled and hemoglobin-A1c-uncontrolled groups. Based on R(2) values, the final model accounted for 20.0% of the variance in self-efficacy, 61.0% of the variance in self-care activities, and 16.0% of the variance in HRQOL. This study suggests that self-care activities are crucial to the link between health literacy and HRQOL. Both health literacy and self-efficacy need to be considered in clinical practice for enhancing self-care activities in patients with type 2 diabetes. This approach may ultimately improve HRQOL in these patients.