Understanding the Growth Hormone Therapy Adherence Paradigm: A Systematic Review

<b><i>Introduction:</i></b> Growth hormone (GH) therapy is used to treat a variety of growth disorders in childhood/adolescence. Its efficacy is thought to be dependent on patients' adherence to their treatment regimen. <b><i>Methods:</i></b> PubMed was searched using the keywords ‘growth hormone', ‘child'[Mesh], ‘adolescent'[Mesh], and ‘patient compliance'[Mesh]. <b><i>Results:</i></b> Most studies of adherence to paediatric GH therapy have used either issued/encashed GH prescriptions or questionnaires. Estimates of prevalence of non-adherence vary from 5-82%, depending on the methods and definitions used. Different studies have variously demonstrated an association (or lack thereof) between adherence and age, socioeconomic status, treatment duration, injection device used and injection-giver. A number of interventions have been proposed to improve adherence, including offering a choice of injection device, but none are supported by trials. Poor adherence is associated with reduced height velocity and likely increased economic costs; evidence for other effects is circumstantial. <b><i>Conclusion:</i></b> Adherence to paediatric GH therapy is suboptimal, which may partially explain why the mean final height attained is below that of the general population. Analysis of the causes of non-adherence is complicated by conflicting evidence from different studies. Multifactorial interventions are most likely to be successful in improving adherence. We make recommendations for further research.