Maintaining persistence and adherence with subcutaneous growth-hormone therapy in children: comparing jet-delivery and needle-based devices

Abstract

Purpose: Persistence and adherence with subcutaneous growth hormone (GH; somatropin) therapy in children is widely acknowledged to be suboptimal. This study aimed to investigate how the use of a jet-delivery device, ZomaJet(®), impacts on medication-taking behaviors compared to needle-based devices.

Materials and methods: A retrospective cohort study of children aged ≤18 years was conducted using a UK-based, nationwide database of GH home-delivery schedules. Data were evaluated for the period between January 2010 and December 2012 for 6,061 children receiving either Zomacton(®) (somatropin) via the ZomaJet jet-delivery device or one of six brands of GH all administered via needle-based devices. Persistence was analyzed for patients with appropriate data, measured as the time interval between first and last home deliveries. An analysis of adherence was conducted only for patients using ZomaJet who had appropriate data, measured by proportion of days covered. Brand switches were identified for all patients.

Results: Persistence with GH therapy was significantly longer in patients using ZomaJet compared to needle-based devices (599 days versus 535 days, respectively, n=4,093; P<0.001); this association was observed in both sexes and across age subgroups (≤10 and 11-16 years). The majority (58%) of patients using ZomaJet were classed as adherent (n=728). Only 297 patients (5%) switched GH brand (n=6,061), and patients tended to use ZomaJet for longer than other devices before switching.

Conclusion: It appears important that the choice of a jet-delivery device is offered to children prescribed daily GH therapy. These devices may represent a much-needed effective strategy for maintaining persistence with subcutaneous GH administration in children, potentially offering better clinical outcomes and greater cost-efficiency.

Keywords: adherence; children; growth hormone; jet delivery; persistence.

Figure 1

Patient disposition and analysis sets. Abbreviations: GH, growth hormone; HAH, Healthcare at Home.

Figure 2

Persistence with growth-hormone treatment in patients using ZomaJet or a needle-based delivery device. Vertical tick marks denote when individual patients desisted with treatment.

Figure 3

Persistence with growth-hormone treatment in patients using ZomaJet or a needle-based delivery device who were (A) aged ≤10 years and (B) aged 11–16 years. Note: Vertical tick marks denote when individual patients desisted with treatment.

Figure 4

Adherence to growth-hormone treatment in patients using ZomaJet. Notes: (A) Distribution of adherence scores; (B) subgroup analyses of adherent patients. ^aUp to eleventh birthday; ^bfrom eleventh birthday up to 17th birthday (the approximate age of epiphyseal fusion). Abbreviation: PDC, proportion of days covered.

Figure 5

Mean duration that patients used a particular growth hormone brand (days) before switching and mean age at switch (years). Note: The arrows represent the direction of switch.