AUTHOR=Loftus Jane , Wogen Jen , Oliveri David , Benjumea Darrin , Jhingran Priti , Chen Yong , Alvir Jose , Rivero-Sanz Elena , Kowalik Jack C. , Wajnrajch Michael P. 

TITLE=Persistence with daily growth hormone among children and adolescents with growth hormone deficiency in the UK

JOURNAL=Frontiers in Endocrinology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.1014743

DOI=10.3389/fendo.2022.1014743

ISSN=1664-2392

ABSTRACT=Background
Children with growth hormone deficiency (GHD) are treated with daily somatropin injections, however poor treatment persistence and adherence has been recognized previously, and has been shown to negatively impact growth outcomes. A recent real-world study of a US pediatric GHD population found that a substantial proportion of children discontinued somatropin therapy, but similar data for a real-world UK population is lacking.
Objectives
To describe discontinuation of, and persistence to, daily somatropin treatment among children with GHD in the UK. 
Methods
This was a retrospective cohort study of children (≥3 and <16 years) with >1 medication prescription for daily injectable somatropin from 1st July 2000 to 31st December 2020 in the IQVIA Medical Research DATA (IMRD) database. Early persistence was defined as the proportion of children prescribed ≥1 somatropin refill (≥2 prescriptions). Discontinuation was defined as the first date at which a medication gap for somatropin (of >60 days or >90 days between prescriptions) occurred. Kaplan-Meier methods were used to evaluate persistence (non-discontinuation) over time to assess time to first discontinuation event. Cox proportional hazards models were used to evaluate the relationship of patient characteristics with time to medication discontinuation. 
Results
Among the cohort identified in this study (n=117), the majority (n=84, 71.8%) had 48 months of available follow-up; 56.4% were male and mean (median) age was 8.6 (8.0) years. About 98% exhibited early persistence, but persistence over the follow-up period decreased with follow-up duration. Using the conservative 90-day gap definition of persistence, an estimated 72.4%, 52.8%, and 43.3% were persistent at 12, 36, and 48 months. Lower persistence rates were observed using the 60-day definition. No significant patient predictors of time to discontinuation were identified.
Conclusions
Despite high early persistence with somatropin, a high percentage of children with GHD were increasingly non-persistent over time. More than 1 in 4 were non-persistent at 12 months and more than 1 in 2 were non-persistent at 48 months follow-up. These results suggest that strategies to support improved medication-taking behavior among children with GHD in the UK are warranted.