A feasibility study of a best practice health literacy app for Australian adults with chronic kidney disease

**Background:** Chronic kidney disease (CKD) is a leading cause of mortality worldwide, with culturally and linguistically diverse populations in Australia bearing a disproportionate burden. Limited health literacy is common in CKD (pooled prevalence 25%) and is associated with adverse clinical events and increased healthcare use. While educational programs for dialysis patients exist, no models of care promote global health literacy skills applicable across multiple decision contexts, tailored to ethnically-diverse and lower literacy groups. The SUCCESS app was developed to address this gap, using a two-pronged health literacy approach: reducing content complexity and improving communicative and critical health literacy skills. This feasibility study aimed to evaluate recruitment capability, data collection procedures, acceptability, and preliminary efficacy of the app.

**Methods:** This multi-centre feasibility study used a pre-post design with mixed-methods evaluation. Haemodialysis patients aged ≥18 years were recruited from five hospitals across four Local Health Districts in Sydney, Australia, between May 2019 and September 2020. Participants used the SUCCESS app for 12 weeks. Quantitative outcomes were assessed at baseline and 12 weeks using validated instruments: the Health Literacy Questionnaire (HLQ) domains 2, 6, and 9; the Decision Self-Efficacy Scale; the Kidney Disease Quality of Life (KDQOL-36); and bespoke measures of health behaviour, knowledge, and confidence. Qualitative semi-structured interviews were conducted with 18 purposively sampled participants at follow-up and analysed using the Framework approach. Paired sample t-tests were used to assess pre-post changes.

**Key Results:** A total of 122 participants were recruited; 116 completed baseline questionnaires (mean age 59.1±14.6 years; 63.8% male; 44.8% born overseas; 43% spoke a language other than English at home; 24% had low health literacy by self-report, 42% low/medium by performance-based measure). Only 61 participants (50%) completed follow-up questionnaires. Those lost to follow-up had significantly greater cognitive impairment (MoCA score 22.1±5.0 vs. 23.8±3.8; p=0.04). Qualitative analysis identified three themes: (i) accessed and useful content was driven by perceived relevance (diet and fluid information most used; Skills for Health section rarely used); (ii) the app was considered most relevant for new dialysis patients; (iii) ongoing engagement required functional improvements (e.g., integration with other apps, notifications) and content additions (e.g., mental health, peer stories). Quantitative analysis showed significant improvements in HLQ Domain 6 'Ability to actively engage with healthcare providers' (Mean Difference [MD]=0.2 on a 5-point scale; 95% CI: 0.0–0.4; p=0.03) and Decision Self-Efficacy (MD=4.3 on a 10-point scale; 95% CI: 0.6–7.9; p=0.02). No significant changes were observed in HLQ Domain 2 ('Having sufficient information to manage my health') or Domain 9 ('Understanding health information well enough to know what to do'). Among KDQOL-36 subscales, only the SF-12 Physical Composite significantly improved (MD=4.4; 95% CI: 2.1–6.6; p<0.01). Health behaviours, knowledge, and confidence showed no statistically significant changes, though some behaviours (e.g., checking nutrition labels: +11%) trended positively. The modified MAUQ indicated high usability (median scores 6–7 out of 7 for satisfaction, usefulness, and willingness to recommend).

**Clinical Implications:** This feasibility study demonstrates that the SUCCESS app is acceptable and may improve key health literacy skills and decision self-efficacy in a diverse haemodialysis population. The high attrition rate (50%) and the finding that participants with greater cognitive impairment were more likely to drop out highlight the need for strategies to support ongoing engagement, particularly for vulnerable patients. The qualitative finding that perceived relevance drives app use suggests that future iterations should better integrate health literacy skills training into content that patients find immediately useful (e.g., diet and fluid management). The app may be most beneficial for patients new to dialysis, but adaptations (e.g., customisable content, reminders, integration with other tools) could extend its utility to those with longer dialysis vintage. These findings support progression to a larger, adequately powered trial to evaluate efficacy, with modifications to enhance retention and engagement.