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Every third adult with childhood-onset GHD has osteoporo- levels of IGF-I can be reduced due to malnutrition, renal in-
sis. Patients with GHD have a 2-5 times greater risk of bone sufficiency, and liver disease . For most patients, stimulati-
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fractures compared to healthy individuals. Histology of on tests for GH are required to establish a diagnosis of GHD,
bones in these patients shows increased bone resorption as except for patients with hypothalamic/pituitary disease
well as increased thickness of the osteoid matrix, indicating who have deficiencies in other pituitary hormones and low
delayed and reduced mineralization . serum IGF-I levels. If one or two hormones of the anterior
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pituitary lobe are deficient, GHD is present in 80% of cases,
Patients with AGHD have increased morbidity and mor- while if three or four pituitary hormones are deficient, GHD
tality due to cardiovascular diseases. Direct effects on the is present in 98% of cases.
heart involve the reduction in mass and diameter of the left
ventricle and interventricular septum. In young individuals, In standard clinical practice, two tests are commonly
a “droplet-shaped heart“ is radiographically described, as used to assess pituitary secretory reserve for GH in adults:
the lack of the anabolic effects of GH leads to a reduction in the Insulin Tolerance Test (ITT) and the Glucose Toleran-
total myocardial mass. Reduction in the diameter of the left ce (GT) test. ITT is considered the "gold standard" for dia-
ventricle, diastolic function, and ejection fraction leads to gnosing GHD, provided that adequate hypoglycemia (blood
the so-called “hypokinetic syndrome“ in these individuals . glucose < 2.2 mmol/L) is achieved. This test is performed
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The consequence of these changes is reduced physical per- under the supervision of a physician in tertiary healthcare
formance and poor tolerance to physical exertion. In AGHD, institutions. It is contraindicated in patients older than 65
there are changes in blood vessels that accelerate athero- years, those with ECG changes, heart failure, cerebrovascu-
genesis, particularly in the carotid arteries and thoracoab- lar disease, epilepsy, and a history of loss of consciousne-
dominal aorta. Specifically, patients with low concentrations ss. An alternative stimulation test used in the diagnosis of
of GH and IGF-I develop thickening of arterial walls, which, AGHD is the glucagon test .
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combined with poor lipid status characterized by increased
total and LDL cholesterol, increases their cardiovascular When glucagon is used as a GH stimulator, delayed re-
risk. lease of this hormone is possible, so it is recommended to
perform the test, i.e., monitoring GH for at least three ho-
It has been shown that patients with GHD have a po- urs. The main drawbacks of the GT include the long dura-
orer Quality of Life (QoL). Several questionnaires are used tion of the test (3 to 4 hours), the need for intramuscular
in practice to assess QoL in these patients. In our practice, administration, and relatively common occurrences of na-
the QoL-AGHDA (Quality of Life of Adult GHD Assessment) usea and vomiting. This test is less specific than the ITT. In
questionnaire is used, which has undergone expert valida- both of these tests, the discriminatory value for diagnosing
tion and translation into our language. This questionnaire GHD is 3 ng/mL for individuals older than 25 years, while for
originated from the examination of the QoL of patients who individuals in the transitional period (18-25 years), this value
had replacement of all other hormones in hypopituitarism is 5-7 ng/mL (15-20 mU/L). Before conducting these tests, it
except for GH . It consists of 25 questions with "YES" or is necessary to adequately replace other hormones (thyroxi-
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"NO" answers, and a higher number of positive responses ne, cortisol). At the end of 2017 in the United States and
indicate poorer quality of life. Although this questionnaire is 2019 in Europe, the FDA and EMA approved the macimore-
an excellent tool for assessing QoL, there is no correlation lin test for diagnosing AGHD. Macimorelin is an orally active
with the severity of GH deficiency. During GH therapy, this ghrelin agonist that is well absorbed in the gastrointestinal
questionnaire is completed every 6 months, the responses tract and effectively stimulates endogenous GH secretion.
are compared, and conclusions about the substitution effe- Macimorelin has been compared to ITT in a multicenter
ct are formed. randomized study, which demonstrated that it is a simple,
reproducible, and safe test, with a GH discriminatory value
Biochemical diagnosis of GHD of 2.8 ng/mL for adults .
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Despite the mentioned clinical signs, the basis for defi-
ning AGHD is biochemical diagnosis. GH secretion is pulsa-
tile, with a half-life of only 19 minutes, so in healthy adults, Growth hormone therapy in adults
GH concentration is almost undetectable. Therefore, mea- The use of GH is indicated in all adult individuals with a
suring serum GH concentration is not valid for proving GHD; complete deficiency of this hormone and the clinical con-
instead, stimulation tests for GH secretion are required. GH sequences of that deficit, if there are no contraindications
secretion depends on gender, age, and body mass index. (see Table 3). In childhood, all patients with GHD, whether
Additionally, a measured low concentration of IGF-I is also it is complete or partial, are treated to achieve satisfactory
not sufficient for diagnosing GHD; it only suggests the need height. On the other hand, in adulthood, GH substitution is
for further testing (Table 2). As serum levels of GH and IGF-I only given to those with complete GHD. The goal of GH the-
decline with aging (somatopause), it is important to diffe- rapy in adults is to normalize IGF-I levels, thereby reducing
rentiate physiological decreases in GH levels from actual morbidity and mortality in individuals with GHD . Due to its
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AGHD, which typically has a recognizable etiology. Serum anabolic and lipolytic effects, growth hormone replacement

REVIEW PAPER Galenika Medical Journal, 2024; 3(9):19-25. 21