ESPE Abstracts

Background: The Growzen™ Buddy app was developed to improve adherence to recombinant human growth hormone (r-hGH) therapy among patients with growth disorders. This app sends alerts for injection timings and allows patients and their caregivers to self-monitor growth, develop a treatment routine, improve adherence, and ultimately take ownership of treatment outcomes. The app also contains a library of educational resources designed to empower patients to play an active role in their treatment. The first-year evaluation of the Growzen™ Buddy app revealed a positive impact on adherence among patients from Argentina.

Aim: To evaluate the world-wide use of the Growzen™ Buddy smartphone app, the impact of the degree of engagement with the app on adherence in the first 2 years of treatment, and the reliability of height measurement values entered by patients.

Method: The activation dates, adherence, and height measurements were extracted from the Growzen™ digital health ecosystem. The mean adherence was classified as optimal (≥85%) and suboptimal (<85%). A reliable measurement of height by the patient was defined as an absolute residual of <0.5 height standard deviation score (HSDS) when fitted with the broken-stick method that also included HSDS data from healthcare professionals (HCPs). This method was applied to the data entered by the patients when the measurement dates fell between those taken by HCPs.

Results: A total of 5,773 patients from 24 countries in Europe, America, and Asia-Pacific registered themselves on the app. The mean age at treatment initiation was 10.3 years, and 57% of them were boys. Overall, 2,388 (41%) patients entered their height data in the app. The proportion of patients with optimal adherence consistently increased as they entered more measurements in the app: 80.6% without measurement, 85.5% with one (P = 0.03), 90.0% with two, and 91.4% with more than 2 measurements (P <0.001) in the first year of treatment. A similar pattern was observed in the second year, with the proportions of optimal adherence as 71.8%, 77.1%, 87.6%, and 91.0%, respectively. Data from 686 patients with 1,584 measurements revealed that 1,559 (98.4%) of these measurements were correctly entered in the app.

Conclusion: Our results indicated that patients who engaged more with the app had better adherence in the first and second years of r-hGH treatment. The majority of patients who entered height data in the app show consistent growth curves in line with HCP measurements.