ESPE Abstracts

Background: Treatment for child GHD requires daily injections, which can be painful and disruptive. For most children, these injections are administered by an adult, usually their parent. Unfortunately, little is known about the burden that a child's treatment places on a parent. The GHD-PTB was developed according to FDA/EMA guidances to address this gap. Items were based on qualitative interviews of 31 parents of children with GHD, ages 4 to <13 years. This study presents the GHD-PTB psychometric validation results.

Methods: A non-interventional, multi-clinic-based study (US/UK) of pre-pubertal children with GHD and parents/guardians of similar children was conducted. Psychometric analyses were completed according to an a-priori statistical analysis plan to determine the measurement model, reliability, validity, responsiveness, and minimally important difference (MID).

Results: The analytic data included 98 parents (mean age children 9.2 years and parents 41.6 years) who were predominantly mothers (80.7%), married (88.1%), and worked (51.0%). Item reduction resulted in an 8-item measure. Factor analyses identified 2 domains: Interference in Daily Life and Emotional Well-being. For each domain and the Overall score, internal consistency reliability was acceptable (Cronbach's alpha >0.70) as was test-retest for Emotional and Overall (>0.70) and slightly lower than expected for Interference (0.60). Convergent validity hypotheses for domains and Overall were proven (P< 0.01, r > 0.40). Known groups validity hypotheses were proven for Emotional, which discriminated between whether the parent gave the injections more often than the child (P<0.05) and the Overall (P=0.05). The length of time their child was on treatment did not discriminate suggesting that treatment continues to be interfering over time. Marked improvements after 12 weeks of treatment were noted for Emotional and Overall (16.6 and 8.6 points). The Interference domain score had a very small improvement. Associated effect sizes were -0.74 (Emotional) and -0.69 (Overall), indicating that the GHD-PTB is sensitive to change at high levels. Preliminary recommendation for the MID is 7 points for the Overall, and 10 for Emotional Well-Being and 6 for the Interference domains.

Conclusions: The GHD-PTB was found to be reliable and valid and is considered ready for inclusion in clinical trials and clinical practice. Since parents are often primarily responsible for administering and ensuring compliance of treatment for young children, accurate and reliable assessment of their treatment burden can help researchers and clinicians better assess the broader range of treatment impacts. Less frequent treatment requirements may reduce this burden for parents.