Endocrine Abstracts

Background: Childhood growth is an indicator of health/well-being. Growth monitoring identifies treatable conditions in apparently healthy children and prevents inappropriate referrals. Systematic growth monitoring is not currently a UK priority and growth disorders are frequently diagnosed late.

Objective: Develop and test the accuracy of GrowthMonitor, an app which enables families to measure a child’s height at home as a cost-effective alternative to primary care growth monitoring.

Methods: ‘GrowthMonitor’ calculates height data using augmented reality. Patients were measured by the app in parallel to stadiometer (gold standard) height measurements as part of routine care. The coefficient of variance assessed repeatability/precision of 3 consecutive app measurements for each patient. Linear regression evaluated the relationship between the app and stadiometer measurements to determine accuracy. The app uses novel algorithms that calculate height compared to UK population-based height references (HSDS), distance from target height (THSDSDEV) and HSDS change over time (ΔHSDS). Predefined cut-offs trigger green (normal), amber (monitor) or red (seek medical advice) alerts.

Results: A total of 79 (42M) patients participated with mean±SD age 10.37±4.1 yr (range 1.9-18.0). The average coefficient of variance for the app measurements was 1.5%, indicating excellent precision. Linear regression showed a clear linear relationship between the app and stadiometer measurements (R² 0.99; P < 0.0001). A Bland-Altman plot gave a bias constant of 0.298, suggesting no consistent bias of either height measurement approach. Of the 12/79 (15%) individuals that triggered red alerts in the app (recommending referral), only 2 (2.5%) were incorrect. According to corresponding stadiometer measurements, these should have triggered amber alerts. One ‘normal’ app measurement was in the amber range according to the stadiometer measurement.

Conclusion: Our preliminary data suggest that the GrowthMonitor app produces accurate, reliable height measurements. This technology could transform the approach to growth monitoring and facilitate early referral/diagnosis of growth disorders.