**Background:** More than 1.2 million children and adolescents (0–19 years) live with type 1 diabetes mellitus (T1DM) worldwide, with incidence increasing by approximately 3% annually. Adolescents face unique challenges including complex daily self-management (blood glucose monitoring, insulin dosing, nutritional estimation) and psychosocial issues such as stigma, diabetes distress, and family conflicts. Health literacy is critical for preventing complications, yet the relationship between digital health interventions and health literacy in this population is poorly understood. This systematic review aimed to provide an overview of the impact of digital health interventions on health literacy in adolescents with T1DM, using Bröder et al.'s (2017) 14-dimension health literacy framework and Duke et al.'s (2018) definition of distal technologies (telehealth, mHealth, game-based support, social platforms, patient portals).
**Methods:** The review followed PRISMA guidelines with a registered PROSPERO protocol (CRD42021282199). Electronic searches were conducted in five databases (Medline, Cochrane Library, EMBASE via Ovid, Web of Science, PsycINFO) from January 2011 to September 2021, with grey literature searches in Google Scholar, OAlster, and Trip. The search was updated on December 29, 2022, with no new relevant results. Inclusion criteria were: T1DM adolescent population, digital health interventions per Duke et al., health literacy per Bröder et al., studies in English/German/French, original peer-reviewed papers or reports (2011–2021). Two researchers independently screened abstracts and full texts; disagreements were resolved by a third reviewer. Quality assessment used RoB2 Cochrane, ROBINS-I, NOS, CASP for primary studies, and Amstar-2 for secondary studies.
**Key Results:** From 981 studies (911 database records + 114 from other sources), 22 studies were included: 11 primary studies (3 RCTs, 1 non-randomized controlled trial, 5 qualitative studies, 1 longitudinal cross-sectional study, 1 quantitative study) and 11 secondary studies (2 systematic reviews, 5 literature reviews, 2 narrative reviews, 2 brief reviews). Sample sizes in primary studies ranged from 12 to 161 (mean 61). Studies originated from USA (8), Ireland (2), Turkey (2), UK (2), Brazil (1), Cameroon (1), China (1), Italy (1), Netherlands (1), Norway (1), Sweden (1), and Taiwan (1). Quality assessment revealed that most primary studies had moderate risk of bias or some concerns; 8 of 11 secondary studies were rated as critically low quality. Only one study (Nkhoma et al., 2021) was assessed as high quality. The most frequently reported health literacy dimension was 'communication and interaction' (Dimension 7), occurring in 25.6% of cases across 11 studies. The second most common was 'knowledge' (Dimension 1) at 18.6% in 8 studies, followed by 'interest and motivation' (Dimension 14) at 14% in 6 studies. The behavioral/operational attribute category was most represented (48.8%), followed by cognitive attributes (27.9%) and affective/conative attributes (23.3%). Social platforms (including social media) were the most prevalent digital intervention type. Key findings included: Pembroke et al. (2021) found that patient engagement and communication increased through reassurance and trust with HCPs. Döğer et al. (2019) reported that WhatsApp was the preferred communication method (57.3% of contacts), followed by phone (29.3%) and SMS (13.4%). Malik et al. (2019) showed social media improved communication outside clinic visits. Contradictory results were noted for self-efficacy and quality of life outcomes across studies using similar interventions.
**Clinical Implications:** The findings suggest that social media and other distal digital tools may serve as beneficial complementary interventions to enhance communication and interaction between healthcare providers and adolescents with T1DM. However, these tools should not replace face-to-face interactions. The review highlights the need for individualized care considering socioeconomic status, patient commitment, and clinical characteristics. The authors emphasize that digital tools require HCP introduction and ongoing encouragement, and that most existing tools are not specifically designed for the T1DM adolescent population. The study calls for a shift from disease-centered to patient-centered care models, with better integration of digital interventions into clinical practice. Further research is needed to determine which specific forms of social media are most suitable for different adolescent subgroups.