medwireNews: Factors including injection exhaustion create barriers to adherence in patients taking growth hormone (GH), but differ between children and adolescents, study findings suggest.

When adherence was assessed with the 8-item Morisky Medication Adherence Scale (MMAS), Mania Radfar (Tehran University of Medical Sciences, Iran) and co-researchers found that just 56.7% of the 81 children aged 2–12 years in their study and 57.9% of the 88 adolescents aged 13–19 years had intermediate/high adherence to GH therapy (MMAS ≥6.0).

However, when assessed by asking patients how many injections they had missed in the preceding month, adherence rates were a corresponding 95.2% and 95.5%. The team attributes this difference to patients’ recall bias, as well as their fear of disappointing their healthcare providers and wish to avoid confrontation when faced with a direct question about their treatment adherence.

Poor adherence in children was associated with forgetting to take GH or to refill the prescription, reported for 22.9% and 14.3% of those with low adherence, respectively. Other factors were being away from home, long-term injection exhaustion (ie, cumulative emotional burden of daily injections), GH shortage, and difficulty accessing a pharmacy that could supply GH, reported for 34.3%, 54.3%, 64.7%, and 64.7%, respectively.

“To overcome these barriers, patient medication reminder systems, longer duration of GH prescription refills, less frequent pharmacy visits and family support can be helpful”, write the researchers in the Journal of Pediatric Endocrinology and Metabolism.

Forgetting to take GH and long-term injection exhaustion were also factors associated with poor adherence in adolescents, and were reported by 18.9% and 48.6%, respectively.

In addition, 28.6% of adolescents with poor adherence complained of painful injections, compared with 6.0% of those with intermediate or high adherence, and 51.4% versus 29.4% had concerns about long-term complications.

Radhar and colleagues believe the latter may reflect a lack of counselling and say that “health care professionals should discuss with patients and their families about the potential adverse effects and the overall safety of GH therapy.”

They also say that the consequences of missing injections should be covered in patient and parent counselling, along with information on the likely final height and the prevention of potential future complications.

The cost of GH was not an issue in this study, because almost all patients were covered by healthcare insurance and only had to cover 10% of the cost.

Persistence with GH (having no treatment gaps of 1 month or longer) was identified in 75.3% of the children and 67.0% of the adolescent groups, respectively. The researchers note that persistence was more common in children with good adherence, “which may signify that barriers might be common to both practices”.

By Eleanor McDermid

J Ped Endocrinol Metab 2017; Advance online publication

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