Quality and Functional Breadth of Publicly Available Mobile Apps Supporting Self-Management After Kidney Transplantation: Cross-Sectional App Store Evaluation

Background Nonadherence to immunosuppressants and other self-management behaviors remains a major challenge after kidney transplantation. Publicly available mobile apps may support long-term self-management, but their quality and functional breadth remain unclear. Objective This study aimed to identify publicly available mobile apps accessible in South Korea that support self-management after kidney transplantation, evaluate their quality and functional breadth using the Mobile App Rating Scale (MARS) and the IMS Institute for Healthcare Informatics functionality score, and describe gaps in transplant-specific self-management support. Methods From January 13 to 21, 2026, we searched the Apple App Store and the Google Play Store using 6 keywords, including “kidney transplant” and “kidney graft,” and selected apps that met the inclusion criteria (n=6). Two trained nursing faculty raters independently evaluated each app using the MARS and IMS functionality score. Interrater reliability was good for the MARS (intraclass correlation coefficient=0.71, 95% CI 0.62-0.78) and the IMS functionality score (Cohen κ=0.88). Results The mean MARS score across the 6 apps was 4.06 (SD 0.96). Subscale scores were highest for aesthetics (mean 4.22, SD 0.81), followed by functionality (mean 4.13, SD 0.80), information (mean 4.11, SD 0.75), and engagement (mean 3.80, SD 1.32). The mean IMS functionality score was 5.67 (SD 4.27) out of 11 functions, and the “evaluate data” function was included in only 1 (16.7%) app. Conclusions Few publicly available apps met the eligibility criteria. Although trained-rater MARS assessments were generally favorable, functions involving data evaluation and individualized guidance or intervention were less frequently implemented. Because the apps differed in their intended purposes and the study did not assess end-user usability or clinical outcomes, the findings should be interpreted as a descriptive baseline rather than evidence of usability or effectiveness. Future studies should involve kidney transplant recipients in patient-centered usability and outcome evaluations.