Psychometric Analysis of the eHealth Literacy Scale in Portuguese Older Adults (eHEALS-PT24): Instrument Development and Validation
Authors: Luz Sara , Nogueira Paulo , Costa Andreia , Henriques Adriana 
Published: October 2024

Background
In this era of digitalization, eHealth interventions are used to engage patients in health care and help them manage their health. Previous studies showed that this can be particularly interesting for chronic disease self-management and self-care in older adults. Despite older adults becoming increasingly active on the internet, they continue to struggle in using eHealth information due to inadequate eHealth literacy. Thus, assessing and monitoring eHealth literacy is critical to support eHealth interventions.

Objective
This study aimed to describe the translation, adaptation, and validation process of the eHealth Literacy Scale (eHEALS) in Portuguese older adults.

Methods
The cross-cultural adaption followed the steps of forward and blinded backward translations, evaluation of the translations by a committee of judges, pilot-testing, and full psychometric testing. We tested the psychometric properties of the eHEALS by carrying out two studies: general psychometric analysis (study 1) and confirmatory factor analysis (study 2). Study 1 included 80 older adults conveniently selected from a Health Family Unit. Data were collected by in-person questionnaires between May and July 2022. Study 2 included 301 older adults randomly selected from two distinct Health Family Units. Data were collected by in-person questionnaires between May and July 2023.

Results
We tested stability, reliability, construct validity (exploratory and confirmatory factor analyses and known groups), and model fit. Study 1 had 58.8% (47/80) male and 41.3% (33/80) female respondents (mean age 71.20, SD 5.26 years). Study 2 had 56.5% (170/301) male and 43.5% (131/301) female respondents (mean age 71.77, SD 5.15 years). Moderate and strong correlations were identified in the scale items (study 1: 0.42≤r≤0.91 and study 2: 0.81≤r≤0.96; P<.001). The scale showed good internal consistency for study 1 (α=.92) and study 2 (α=.98), with high correlations between items. The exploratory factor analysis yielded a single-factor structure, explaining 58.3% of the variance in study 1 and 86.4% in study 2. In the confirmatory analysis (study 2), the model fit was mixed (χ²20=265, P<.001; comparative fit index=0.94; Tucker-Lewis Index=0.91; root mean square error of approximation=0.20). Thus, we compared 1-, 2-, and 3-factor structures, deciding on the unidimensional one. In study 1, the eHEALS-PT24 (Portuguese version of the eHealth Literacy Scale for older adults) mean score was 27.25 (SD 5.61), with 43.8% (35/80) and 11.3% (9/80) of participants showing low and high eHealth literacy levels, respectively. In study 2, the eHEALS-PT24 mean score was 23.31 (SD 9.53), with 38.2% (115/301) and 23.6% (71/301) of participants showing low and high eHealth literacy levels, respectively. The known-groups analysis showed statistically significant differences between eHealth literacy and demographic variables (P<.001).

Conclusions
The findings suggest that the eHEALS-PT24 is a reliable and valid tool to assess eHealth literacy in Portuguese older adults. Therefore, this instrument can be integrated to support the implementation process of eHealth interventions.