Growth hormone (GH) therapy is a medical treatment primarily used to address growth failure in children caused by Growth Hormone Deficiency (GHD) or certain other conditions leading to short stature. This therapy uses recombinant human GH to stimulate growth and metabolic function. While the goal in children is to achieve a normal adult height, the decision to discontinue the medication is complex. Stopping GH depends on whether the patient has reached the end of physical growth or requires continued treatment for metabolic reasons in adulthood. Determining the right time to stop involves assessing clinical, radiologic, and biochemical markers to ensure optimal long-term health outcomes.
Defining the End of Pediatric Growth
The decision to stop GH therapy in an adolescent is based on objective evidence that the treatment is no longer effective for increasing height. Endocrinologists primarily assess skeletal maturity using a bone age X-ray of the hand and wrist. This radiologic assessment indicates the remaining growth potential before the growth plates fuse.
Therapy is typically discontinued when the patient has reached near-final adult height and the growth plates are close to closure. A common guideline suggests stopping treatment when a boy’s bone age reaches 16 years or a girl’s bone age reaches 14 years. These ages represent the point where most linear growth has concluded, making further treatment ineffective.
Another practical marker for cessation is a significant decline in height velocity, or the rate of growth. When a patient’s growth rate drops below 2 centimeters per year, it indicates that the growth plates are nearing complete fusion. Continuing GH injections beyond epiphyseal closure does not contribute to further height gain.
The final decision is individualized, considering the patient’s overall health, puberty stage, and the underlying cause of their disorder. Treatment is stopped once physical growth is complete, even if the patient has not reached their target height.
Managing Ongoing Treatment for Adults
For individuals whose Growth Hormone Deficiency persists after linear growth has ended, management shifts from promoting height to maintaining metabolic health. This includes patients with persistent childhood-onset GHD and those who develop Adult GHD (AGHD) later in life. For many adults with confirmed GHD, GH therapy becomes a long-term replacement regimen to support overall health.
The criteria for managing adult GH therapy are based on biochemical and clinical markers, not physical growth. The primary biochemical marker is Insulin-like Growth Factor-1 (IGF-1), a hormone produced by the liver in response to GH. The goal is to maintain serum IGF-1 levels within the middle of the age-adjusted normal range, ensuring adequate replacement without causing side effects.
Cessation of GH therapy in adults is rare, usually only considered if the deficiency was temporary or if the patient experiences unmanageable side effects. For most, treatment involves dosage adjustment or titration based on IGF-1 levels and clinical symptoms. Dosing starts low and is gradually increased, with adjustments made based on clinical response and IGF-1 results.
Continued treatment in adults is important for maintaining body composition, as GH influences muscle mass and fat distribution. It also plays a role in bone density, lipid metabolism, and overall quality of life, including energy levels and mood. The decision to maintain treatment centers on sustaining these long-term health benefits.
Monitoring and Follow-Up After Therapy Ends
Once GH therapy is discontinued in an adolescent who has reached final height, monitoring and re-evaluation are necessary. This process determines if the patient has a permanent GH deficiency requiring continued treatment at adult doses. Retesting is usually performed after a four to six-week washout period, allowing exogenous GH to clear from the body.
The re-evaluation typically involves a Growth Hormone Stimulation Test. During this test, a medication is administered to provoke the pituitary gland to release GH. The measured peak GH level indicates whether the patient’s body can produce an adequate amount of the hormone naturally. A significant percentage of children diagnosed with idiopathic GHD may have normal GH secretion upon retesting as adults.
If the stimulation test confirms persistent GHD, the patient transitions to adult endocrine care and starts a lower GH replacement dose for metabolic needs. For those with organic causes of GHD, such as a pituitary tumor, retesting may not be necessary as the deficiency is generally permanent. The transition from pediatric to adult care requires careful coordination to ensure continuous medical oversight.
Long-term follow-up includes regular assessments of metabolic and bone health. This monitoring may involve checking fasting lipids, glucose levels, and bone mineral density over time. Maintaining adequate GH replacement supports optimal peak bone mass and reduces the risk of cardiovascular and metabolic complications associated with the deficiency.