ESPE Abstracts

Background: Children with growth hormone deficiency (GHD) may have to deal with practical, emotional, and functional difficulties. Unfortunately, to date, there is no condition specific measure of the impact of GHD for these children. The Growth Hormone Deficiency – Child Impact Measure (GHD-CIM) was developed according to FDA/EMA guidances to address this gap. There are two GHD-CIM versions: child self-report (PRO) for ages 9 to <13 years and observer-report (ObsRO) for parents/guardians of children 4 to <9 years. Items are based on qualitative interviews with 39 children and 31 parents. This study presents the GHD-CIM psychometric validation results.

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

Results: The analytic data set was 243 subjects (145 children and 98 parents/guardians). Children's average age was 9.2 years, they were 72% male, and average age at diagnosis was 6.9 years. Item reduction resulted in a 20-item measure. Factor analyses identified 3 domains: Physical Functioning, Social Well-being, and Emotional Well-being. Internal consistency reliability was acceptable for all domains and the Overall score (Cronbach's alpha >0.70) as was test-retest reliability for the Emotional and Overall (above 0.70) although test-retest reliability was slightly lower than expected for the Physical (0.59) and Social (0.65). At least one of the convergent validity hypotheses for each domain and Overall was proven (r > 0.40). Known groups validity hypotheses for the Emotional and Social Well-being domains were significant (P <0.05) and a trend for the Physical Functioning and Overall. All GHD-CIM domains and Overall were able to significantly discriminate between levels of emotional well-being. Associated effect sizes ranged from -0.44 to -0.49, indicating that the GHD-CIM is sensitive to change. Anchor based patient and clinician ratings of severity of disease suggest a preliminary MID of 5 points for the Overall score, 5 for Physical Functioning, 7 for Emotional Well-Being, and 5 for the Social Well-Being domains.

Conclusions: The GHD-CIM was found to be reliable and valid and is considered ready for inclusion in clinical trials and clinical practice. Accurate and reliable assessment of disease burden can help researchers and clinicians better assess and address impacts of disease, factors that may affect treatment compliance, and may improve doctor-patient communications.