Сompliance and barriers to growth hormone therapy in children

Introduction
To compare the level of compliance to recombinant human growth hormone (rGHh) therapy depending on the methods of its measuring and identify social/demographic, cognitive/emotional and medical factors (barriers) that influence adherence to treatment of children with growth hormone deficiency (GHD).

Material and methods
The study group included 80 children with GHD at the age of 7.1 ±0.4 years. The assessment of adherence to rGHh therapy was carried out by the self-report method and the Morisky Medication Adherence Scale (MMAS). Social/demographic, cognitive/emotional, and medical factors were considered as potential barriers compliance. The categorical variables were expressed as frequency (percentage) and analyzed by χ2-test. A p-value < 0.05 was considered as statistically significant.

Results
Comparison of two methods of measuring adherence to rGHh therapy demonstrates the advantages of using the MMAS. The self-report method overestimates the compliance . Children with unacceptable adherence were more likely to have such social/demographic factors as below average income, rGHh shortage and being away from home. Cognitive/emotional barriers to compliance included forgetfulness/ preoccupation, fear of injections, and treatment fatigue. Medical factors that impeded the development of acceptable compliance included insufficient patient/parents counseling, use of conventional syringe instead of automatic pen devices. Implementation of the compliance support program increased the frequency of acceptable (high and medium) adherence to rGHh therapy to 80.0% compared to the baseline level of 57.4% (p = 0.002).

Conclusions
Adequate assessment of compliance to rGHh therapy depends on the choice of measurement method. An individual compliance support program based on the results of identification of barriers contributes to an increase in the adherence to rGHh therapy in children with GHD.