User Engagement With the CamAPS FX Hybrid Closed-Loop App According to Age and User Characteristics

CamAPS FX (CamDiab, Cambridge, U.K.) is a hybrid closed-loop app hosting the Cambridge closed-loop algorithm on an Android smartphone, and it is approved in the European Union for use in children ≥1 year and adults (including during pregnancy) with type 1 diabetes (T1D). The interoperable CamAPS FX app receives glucose data from a compatible continuous glucose monitoring system (Dexcom G6; Dexcom, San Diego, CA), connects to a compatible insulin pump (Dana Diabecare RS and DANA-i; Sooil, Seoul, South Korea) to direct glucose-responsive insulin delivery every 8–12 min, includes a bolus calculator allowing discrete bolusing via the app, and streams data in real time to cloud-based diabetes data repositories (Diasend/Glooko, Gothenburg, Sweden). It is currently unknown how much time different user cohorts spend interacting with hybrid closed-loop systems. We aimed to investigate usage patterns of the CamAPS FX app across different populations by considering the amount of time a person spends using the app over a 24-h period. We noted time spent within the CamAPS FX app over an 11-week period from February to May 2020 in 134 individuals from six ongoing clinical studies. Each study involved a different demo graphic cohort: very young children (1–7 years) in which caregivers use the app (NCT03784027, ClinicalTrials.gov), children and adolescents (6–19 years) (NCT02925299), adolescents (10–17 years) using the closed-loop system from diagnosis of T1D (NCT02871089), adults (≥18 years) (NCT04055480), pregnant women (≥18 years) (ISRCTN56898625, www.isrctn.org), and older adults (≥60 years) (NCT04025762). All studies received regulatory and ethical approval; participants/guardians signed informed consent. User engagement is the duration of time that users have the application active and in the foreground, as calculated by an analytics cloud platform (Firebase; …