Psychometric Validation of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM)

Meryl Brod; Michael Højby Rasmussen; Knud Vad; Suzanne Alolga; Donald M Bushnell; Jacques Bedoin; Aristides Maniatis

doi:10.1007/s41669-020-00252-5

Psychometric Validation of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM)

Pharmacoecon Open. 2021 Sep;5(3):505-518. doi: 10.1007/s41669-020-00252-5. Epub 2021 Jan 12.

Authors

Meryl Brod¹, Michael Højby Rasmussen², Knud Vad², Suzanne Alolga³, Donald M Bushnell⁴, Jacques Bedoin², Aristides Maniatis⁵

Affiliations

¹ The Brod Group, Mill Valley, CA, USA. mbrod@thebrodgroup.net.
² Novo Nordisk A/S, Søborg, Denmark.
³ The Brod Group, Mill Valley, CA, USA.
⁴ Health Research Associates, Inc, Mountlake Terrace, WA, USA.
⁵ Rocky Mountain Pediatric Endocrinology, Centennial, CO, USA.

Abstract

Objective: The aim of this study was to perform psychometric testing of the Growth Hormone Deficiency-Child Impact Measure (GHD-CIM): a patient-reported outcome (PRO) for children with GHD aged 9 to < 13 years and an observer-reported outcome (ObsRO) for parents/guardians of children who are unable to answer for themselves.

Methods: A non-interventional, multicenter, clinic-based study was conducted in 30 private-practice and large institutional sites in the US and the UK. Psychometric analyses were conducted following an a priori validation statistical analysis plan.

Results: A preliminary examination of the data determined a PRO version for children aged 9 to < 13 years was not psychometrically sound and therefore the decision was made to have only an ObsRO measure of the GHD-CIM, which would be suitable for children aged 4 to < 13 years. The GHD-CIM ObsRO validity analyses included 98 parents/guardians. Factor analyses identified three domains: Physical Functioning (PHYS), Social Well-Being (SWB), and Emotional Well-Being (EWB). Internal consistency reliability was acceptable for all domains and for the overall score (Cronbach's alpha > 0.70), as was test-retest reliability for the SWB, EWB and overall (above 0.70). At least one convergent validity hypotheses for each domain and overall was proven (r > 0.40). Known-groups validity hypotheses for the EWB and SWB domains were significant (p < 0.05). Associated effect sizes ranged from - 0.40 to - 0.58, indicating that the GHD-CIM is sensitive to change. Anchor-based patient and clinician ratings of severity of disease suggest a preliminary minimally important difference of 5 points for the overall score, and 5 for PHYS, 7 for EWB, and 5 for SWB.

Conclusions: The GHD-CIM ObsRO was found to be a reliable and valid measure to assess disease-specific functioning, which will provide a more complete patient-centric picture to the growth hormone therapy experience in children.

Trial registration: ClinicalTrials.gov NCT02580032, first posted 20 October 2015.

Associated data

ClinicalTrials.gov/NCT02580032