Indications for Growth Hormone Treatment
Growth hormone therapy is indicated for specific FDA-approved conditions in both pediatric and adult populations, with the strongest evidence supporting treatment for confirmed growth hormone deficiency (GHD) and several well-defined syndromic and non-GHD causes of short stature.
Pediatric Indications
The FDA has approved 8 primary indications for recombinant human GH (rhGH) therapy in children 1:
Confirmed Indications:
- Growth hormone deficiency (the original and most established indication)
- Turner syndrome
- Prader-Willi syndrome
- Small for gestational age (SGA) without catch-up growth
- Idiopathic short stature
- SHOX gene haploinsufficiency
- Noonan syndrome
- Chronic renal insufficiency/chronic kidney disease 2, 1
Dosing Considerations:
Pediatric dosing should be individualized, typically ranging from 25-50 μg/kg/day in the United States, with doses up to 100 μg/kg/day utilized during puberty 2. The goal is to use the lowest effective dose that optimizes growth velocity.
Adult Indications
For adults, GH therapy is approved specifically for confirmed adult growth hormone deficiency (AGHD), with benefits demonstrated in body composition, bone health, cardiovascular risk factors, and quality of life 3.
Adult GHD Categories 3:
- Childhood-onset GHD transitioning to adulthood
- Adult-onset GHD secondary to structural lesions or trauma
- Idiopathic adult GHD
Critical Caveat for Transition Patients:
Patients with childhood-onset GHD who achieve adult height must be retested for GHD as adults UNLESS they have:
- Known genetic mutations
- Embryopathic lesions causing multiple hormone deficits
- Irreversible structural lesions/damage 3
This retesting requirement exists because many children with idiopathic GHD may not have persistent deficiency in adulthood.
Diagnostic Requirements
For Pediatric GHD:
- Peak GH levels during stimulation testing are used for diagnosis
- Pituitary abnormalities are more likely with peak GH <5 ng/mL, especially in children with multiple pituitary hormone deficiencies 2
- MRI findings such as ectopic posterior pituitary (EPP) and hypoplastic anterior pituitary have high specificity for predicting GHD 2
For Adult GHD:
Appropriate GH stimulation testing with validated cut-points is essential before initiating therapy 4. The diagnosis requires:
- Clinical suspicion based on hypothalamic-pituitary disorders
- Confirmatory stimulation testing (insulin tolerance test, glucagon stimulation test, or arginine stimulation test)
- Appropriate interpretation considering assay variability 4
Monitoring During Treatment
Pediatric Monitoring:
- Annual IGF-I measurements are recommended
- Dose adjustments should be considered when IGF-I levels exceed +2 standard deviation score (SDS)
- For GHD patients with adequate catch-up growth, maintaining IGF-I at 0 SDS is appropriate 2
Adult Monitoring:
Individualized dose adjustments based on age, gender, body mass index, and IGF-I levels have improved effectiveness and reduced side effects 4.
Important Exclusions
GH therapy is NOT approved for anti-aging treatment 3. This unapproved use should not be pursued, as the risk-benefit profile has not been established for this indication.
Safety Considerations
Long-term surveillance is required for:
- Glucose intolerance risk
- Pituitary/hypothalamic tumor recurrence
- Cancer risk (though data are largely reassuring after 3+ decades of use) 3, 5
The decision to treat requires thoughtful, individualized evaluation of benefits versus risks, with periodic reevaluation of treatment warranted 3.