Associations of Health Literacy and eHealth Literacy With Patient Portal Access and Use: Systematic Review

BACKGROUND Effective patient portal access and use require both digital navigation and understanding of clinical information. Health literacy and eHealth literacy reflect these different demands. Although the 2 constructs overlap, prior research often treats them as interchangeable. It remains unclear whether health literacy and eHealth literacy are associated differently across stages of portal engagement and patterns of portal use. A systematic review is therefore needed to identify consistent patterns across studies. OBJECTIVE This study aimed to synthesize associations of health literacy and eHealth literacy with patient portal access, general use, feature-specific use, and frequency of use. METHODS We searched PubMed, Scopus, CINAHL, PsycINFO, Web of Science, and Embase from inception to March 2026 using keywords related to health literacy, eHealth literacy, patient portals, and portal access or use. We included English-language peer-reviewed articles and gray literature involving adults who used real-world patient portals, measured health literacy or eHealth literacy using validated instruments, and reported quantitative associations with portal access or use. Because studies differed substantially in literacy instruments, portal outcomes, and outcome measures, we used direction-based vote counting, complemented by narrative synthesis. Reporting followed the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statement, whereas synthesis methods were guided by the Cochrane Handbook for synthesis without meta-analysis. For full-text, peer-reviewed journal articles, we assessed the risk of bias by using the Joanna Briggs Institute (JBI) critical appraisal tools. RESULTS Among 1107 screened studies, 30 met the inclusion criteria. Of these, 17 examined health literacy only, 10 examined eHealth literacy only, and 3 examined both constructs in the same sample. Studies focused far more on portal use than on portal access and emphasized general portal use over feature-specific outcomes. Any use was assessed more often than frequency of use. Nine of 10 directionally codable eHealth literacy studies of general portal use showed lower use among individuals with lower eHealth literacy, whereas health literacy findings for general portal use were mixed. Lower health literacy showed a more consistent pattern of lower portal access and several feature-specific outcomes, although comparable eHealth literacy evidence for these outcomes was limited. Most studies met the majority of JBI criteria, although most measured portal use via self-report rather than objective system data. CONCLUSIONS Nearly every directionally codable eHealth literacy study reported lower portal use among patients with lower eHealth literacy. Lower health literacy showed similar patterns for portal access and several feature-specific outcomes. These consistent associations point to literacy-related disparities at multiple stages of portal engagement, although comparable within-sample evidence remains limited. Future studies should measure both constructs in the same sample, use comparable modeling approaches, use objective portal log data when possible, and distinguish access, any use, frequency, and feature-specific behaviors to identify where literacy-related disparities emerge. CLINICALTRIAL