Most authorities recognise adult growth hormone deficiency (AGHD) as a distinct endocrine disorder, although determining an appropriate strategy for optimising replacement remains controversial.
We reviewed the outcome of a cohort of patients treated with a fixed graded initiation phase followed by an individualised titration phase. Patients were initiated on a starting dose of 0.3 mg recombinant human growth hormone (rhGH) for one month, with increases to 0.4 mg and 0.5 mg at monthly intervals, during which increases were made unless adverse symptoms arose. After three months, further dose titration was made aiming for a target IGF-I between the mean and +2 S.D. taking into consideration the patients symptomatic response.
Analysis was restricted to patients initiated on rhGH after 2003 with the standardisation of IGF-I measurement to the Nichols chemiluminescent assay. Subjects were included where AGHD was diagnosed on the basis of (1) structural pituitary disease, (2) peak GH response less than 9 mU/L after provocative testing and (3) initial rhGH dose of 0.3 mg with initial monthly increments. Outcome measures for this retrospective analysis were the percentage of patients achieving an IGF-I greater than the age-related mean after 3, 6 and 24 months, and the frequency of adverse events.
66 patients initiated since 2003 met inclusion criteria. An IGF-I level greater than the age-related mean was achieved in 74% (3 months), 78% (6 months) and 81% (24 months, n=47). Adverse events relating to rhGH treatment were noted in 13.6% and 12.6% at 3 and 6 months but no patients had adverse events at 24 months. 15% of patients had an IGF-I level above the reference range at 24 months.
A fixed graded initiation phase of GH replacement achieves a rapid resolution of GH deficiciency with a small number of patients experiencing adverse events although a significant number with IGF-I above the normal range.