Table 3.

Overview of the included studies.

Study	Measurement of eHealth Literacy (Validity or Reliability)	HIV-Related Health Outcome	Main Findings
Blackstock et al, 2016 [28]	eHEALSa Dichotomized at the median (high vs low health literacy; alpha=.88)	HIV transmission risk behaviors, including condomless vaginal or anal intercourse, and any illicit drug use in the previous 30 days	Higher eHealth literacy, AORb 3.90 (95% CI 1.05-14.56), significantly associated with HIV transmission risk behaviors, adjusted for income and self-perceived health status.
Kim et al, 2015 [29]	Study questions: “Are you able to read?” and “Are you able to write?” (validity or reliability not reported)	Viral suppression (CD4c count), adherence to ARTd	Literate mobile phone users had lower adherence to ART (84.2% vs 90.6%; P=.007) and more favorable perception of utilizing reminders to support the adherence to treatment (57.1% vs 36.7%; P<.001) than those who were either illiterate, did not have a mobile phone, or both. There was no difference between literate mobile users and other study participants in the virological suppression.
Krishnan et al, 2015 [30]	Short Test of Functional Health Literacy in Adults (validity or reliability not reported)	ART adherence	No significant differences were found in communication technology use and mHealth acceptance among participants with alcohol use disorders, depression, and suboptimal ART adherence.
Ownby et al, 2012 [26]	TOFHLAe<59, inadequate; 60-74, marginal; >75, adequate (validity or reliability not reported)	Medication adherence	Changes in the adherence only approached the statistical significance. Knowledge and behavioral skills increased over the course of the study.
Robinson et al, 2010 [27]	eHEALS (validity or reliability not reported)	HIV-related health outcome not measured	A significant improvement from the baseline to immediately following the intervention was observed in perceived eHealth literacy levels (mean summary score 19 vs 32, P<.01) and perceptions of ability to use the internet (P<.05).
Siedner et al, 2015 [24]	Participants were asked to read a complete sentence in the local language (validity or reliability not reported)	Retention in care defined as a return to the clinic within 7 days of the first SMSf text message for those with abnormal results or on the date of the scheduled appointment for those with normal results	The ability to read a complete sentence on enrollment was independently associated with accurate identification of the message sent, AOR 4.54 (95% CI 1.42-14.47), and return to the clinic within 7 d of the first transmitted SMS text message, AOR 3.81 (95% CI 1.61-9.03). An ability to access an SMS text message on enrollment was independently associated with returning to the clinic within 7 days of an abnormal SMS text notification, AOR 4.90 (95% CI 1.06-22.61).
Woods et al, 2016 [25]	TOPSg; TOHRNh; eHEALS; Rapid Estimate of Adult Literacy in Medicine; HIV Knowledge 18; Expanded Numeracy Scale; TOFHLA; Short Assessment of Health Literacy; Newest Vital Sign (validity or reliability not reported)	CD4 count and HIV plasma viral load	Lower TOPS scores were associated with fewer years of education (ρ=.49, P=.003), higher HIV viral load (correlation=−.47, P=.006), less frequent computer and internet use (P<.05) and not owning a smartphone (P<.05); lower TOHRN scores were associated with lower education (ρ=.40, P=.01), higher HIV viral load (ρ=–.032, P=.045), less frequent internet use (P<.05), and anxiety related to computer use (P<.05).

^aeHEALS: eHealth Literacy Scale.

^bAOR: adjusted odds ratio.

^cCD4: cluster of differentiation 4.

^dART: antiretroviral therapy.

^eTOFHLA: Test of Functional Health Literacy in Adults.

^fSMS: short message service.

^gTOPS: Test of Online Pharmacy Skills.

^hTOHRN: Test of Online Health Records Navigation.