Adherence to Daily Growth Hormone Therapy in Japan: Real-World Data from the Melon Nikki™ App and Device

Context Since 2020, growth hormone (GH) therapy administered using electronic drug delivery devices (GROWJECTORTM L) linked to a smartphone application (Melon NikkiTM) has been approved in Japan. Real-world data generated through this system enable evaluation of treatment adherence among pediatric patients receiving GH therapy. Objectives To assess adherence to home-based GH self-injection using a smartphone application linked to an electronic injection device and identify factors associated with adherence. Design Observational study Setting Real-world data were collected and analyzed, including home injection patterns, GH dosage, and changes in height and body mass index over the first year of therapy. Factors significantly associated with adherence outcomes were evaluated using statistical analyses. Patients We enrolled a cohort of Japanese pediatric patients with various indications for GH therapy who used an electronic injection device connected to the Melon NikkiTM application. Results Injection adherence declined after the second month in patients with GH deficiency and after the fourth month in patients born small for gestational age, particularly among those with variable injection times. Multivariate analysis showed that cumulative app usage up to 24 weeks is an independent factor that significantly contributes to an increase in the cumulative injection rate. Use of the application was associated with better adherence during initial 8 weeks. Conclusions Use of a smartphone application linked to an electronic injection device may support adherence maintenance during the early phase of GH therapy. These findings provide clinically relevant insights that may inform patient guidance and adherence-focused interventions.