A study protocol evaluating the effectiveness of the older adult's digital health literacy (ODDHeaL) intervention.

Digital health literacy (DHL) is recognised as a vital determinant of healthy ageing, directly influencing the ability of older adults to navigate an increasingly technology-driven healthcare landscape. Despite increasing internet penetration, overall DHL among the elderly remains significantly low. Guided by the social cognitive theory (SCT), the ODDHeaL intervention module aims to improve the DHL of the community-dwelling older adults. A single-blinded, two-arm cluster randomised controlled trial was conducted to evaluate the Older Adults Digital Health Literacy (ODDHeaL) module. Individuals aged 55 years and older who own a smartphone with their own internet access, and, having normal M-ECAQ and Katz ADL scores, will be included in the study. The development of the ODDHeaL module or intervention was systematically guided by the ADDIE model, with the content developed based on an extensive literature review and input from experts from related fields. The newly developed module was tested across six clusters, which were randomly allocated to intervention and control groups and evaluated at baseline, immediately, and 2 months after the intervention. An intention‑to‑treat approach will be used during the analysis. This study may reveal the positive effects of the ODDHeaL intervention module on DHL among older adults, as well as health literacy, perception towards online health information, self-efficacy and health information-seeking behaviour (HISB). With improved DHL, older adults are expected to have better disease self-management by transforming them from passive recipients of care into active participants in their own health. This study was prospectively registered with the Thai Clinical Trials Registry (TCTR20250811007) on 11 August 2025, prior to participant enrolment.