Prevalence of refractoriness when testing growth hormone levels in children

Area of Science:

• Pediatric Endocrinology
• Growth Hormone Physiology
• Diagnostic Testing

Background:

• Spontaneous nocturnal growth hormone (GH) secretion patterns may impact the pituitary's response during provocative testing.
• Understanding these influences is crucial for accurate diagnosis in children with growth disorders.

Purpose of the Study:

• To evaluate the GH response during the arginine-insulin-tolerance test (AITT) following a GH peak observed during a short spontaneous nocturnal profile (SSNP).
• To identify factors influencing GH testing refractoriness in children with short stature or low growth velocity.

Main Methods:

• Retrospective review of medical records from 257 children (aged 4-18 years) undergoing SSNP and AITT.
• Definition of refractory children as those with a GH peak ≥7 μg/L during SSNP but not during AITT.
• Analysis of clinical characteristics, timing between tests, and inter-hospital variations.

Main Results:

• 21.9% of children with a GH peak during SSNP or AITT were classified as refractory.
• Refractory children showed a higher proportion of males and higher BMI standard deviation scores.
• The timing between the last nocturnal GH peak and maximal GH during AITT varied, with earlier peaks in non-refractory cases.

Conclusions:

• A notable proportion of children with short stature exhibit refractoriness in GH testing.
• Few distinct clinical characteristics were identified in refractory cases.
• Procedural variations may influence refractoriness and should be considered during GH response evaluation.