Managing Growth Hormone Deficiency Across the Continuum of Care - Episode 4
Growth Hormone Deficiency in Adults — Presentation, Quality of Life, and Diagnostic Challenges
How pediatric endocrinologists evaluate poor growth: key labs, IGF-1/IGFBP-3, stimulation testing, and ruling out celiac, Crohn’s, thyroid disease.
This episode explores adult-onset GHD: how it presents, why it is so frequently missed, and the significant challenges clinicians face in achieving a biochemical diagnosis.
Dr. Agrawal opens by explaining that adult GHD lacks the clear growth-velocity signal that defines the pediatric condition. Instead, it manifests as a constellation of nonspecific symptoms: fatigue, low energy, low mood, depression, reduced cognition, central adiposity, loss of lean body mass, insulin resistance, and elevated cholesterol. These symptoms are often attributed to normal aging — leading to delayed or missed diagnoses — despite meaningful treatment options being available.
Dr. Garcia then outlines the diagnostic pathway for adults. The first step is identifying patients at risk: those with a history of pituitary tumor, surgery, radiation, or head trauma. Because GH is secreted in pulses, random serum GH levels are diagnostically useless. IGF-1 is helpful when pan-hypopituitary patients have an IGF-1 ≥2 SD below the mean — a scenario where dynamic testing may be waived — but a normal IGF-1 does not rule out GHD.
The reference standard for adult GHD diagnosis is the insulin tolerance test (ITT), but it is resource-intensive, requires continuous physician supervision, is uncomfortable for patients, and is contraindicated in those with coronary disease or seizure history. The glucagon stimulation test (GST) has become the primary alternative in the U.S. — though it is off-label and takes 4–6 hours.
Macimorelin — the only FDA-approved GH provocative test — is currently unavailable in the U.S., representing a significant unmet need. The panel agrees that broader availability would be transformative.
Panelists note that the number of dynamic tests needed (one vs. two) depends on the clinical pre-test probability and insurance requirements. The panel acknowledges a widespread training gap, as many adult endocrinologists are unfamiliar or uncomfortable with GH stimulation testing.
In the next episode, “Unmet Needs in Growth Hormone Deficiency Management,” the panel examines the most pressing gaps in GHD care, from diagnostic limitations to education and access challenges.
