Comparison of low-normal and high-normal IGF-1 target levels during growth hormone replacement therapy: A randomized clinical trial in adult growth hormone deficiency

• DOI: 10.1016/j.ejim.2016.03.026
• Publication Date: 2016-04-30T18:40:19Z
• Authors: Christa C. van Bu...; Paul Lips; Mark H. Kramer; Madeleine L. Drent
• Keywords: Adult; Male; Sex Characteristics; Hormone Replacement Therapy; Human Growth Hormone; Cholesterol, HDL; Myalgia; Middle Aged; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; SDG 3 - Good Health and Well-being; Reference Values; Risk Factors; Journal Article; Humans; Female; Insulin-Like Growth Factor I; Waist Circumference; Fatigue; Netherlands

Current guidelines state that the goals of growth hormone (GH) therapy in adults should be an appropriate clinical response, avoidance of side effects, and an IGF-1 value within the age-adjusted reference range. There are no published studies on the target level for IGF-1 that offer specific guidance in this regard.To compare low-normal and high-normal target levels of IGF-1 on efficacy and safety of GH treatment.A randomized, open-label, clinical trial including thirty-two adults from one university hospital receiving GH therapy for at least one year with a stable IGF-1 concentration between -1 and 1 SD score (SDS). Subjects were randomized to receive either a decrease (IGF-1 target level of -2 to -1 SDS) or an increase of their daily GH dose (IGF-1 target level of 1 to 2 SDS) for a period of 24weeks. The effect on cardiovascular risk factors and physical performance, next to tolerability, was compared.Thirty subjects (65.6% men, mean age 46.6 (SD 9.9) years) could be analyzed. In subjects with a high-normal IGF-1 target level, waist circumference decreased (p=0.05), and overall they felt better (p=0.04), compared to subjects with a low-normal IGF-1 target level. However, increasing IGF-1 levels led to more myalgia, and decreasing IGF-1 levels to more fatigue. There was a gender-dependent difference in effect on HDL cholesterol.Although increasing GH dose to IGF-1 levels between 1 and 2 SDS improved waist circumference and well-being, safety was not guaranteed with the demonstrated effect on HDL cholesterol in men, and reported myalgia.