Optimal final adult height achieved by low-dose recombinant human growth hormone therapy

Abstract

Background Thailand has been administering the recombinant human growth hormone (rhGH) treatment for >20 years. Due to limited resources being available, efforts have been directed toward utilizing rhGH at the lowest feasible dose. However, there is currently a lack of evidence in terms of the efficacy and outcomes. Objective To evaluate the auxological outcomes of growth hormone (GH) treatment and the GH secretion ability after reaching final adult height (FAH) and discontinuing rhGH. Methods Data of 40 patients were retrospectively reviewed. The clinical characteristics, auxological data, and results of biochemical and endocrine investigations before and during rhGH treatment were evaluated. In addition, GH retesting was performed in 24 patients using the insulin tolerance test. Results Twenty patients (50%) had complete growth hormone deficiency (GHD), defined as peak stimulated GH level <5 ng/mL, and the remaining patients had partial GHD. Most patients were male (n = 25, 62.5%). The mean age at which rhGH was initiated was 8.9 years. Patients with partial GHD received a higher dose of rhGH than those with complete GHD (30.9 µg/kg/d vs. 26.2 µg/kg/d, P = 0.02). Patients with complete and partial GHD reached FAH at height standard deviation scores (SDSs) of −0.65 and −1.47, respectively. The factors associated with obtaining a good clinical response in terms of height gain included peak-stimulated GH level, age of puberty, and age of discontinuing rhGH. After completing the rhGH treatment, 13 of the 24 patients showed normal GH secretion. Patients with multiple pituitary hormone deficiency (MPHD) were likely to have persistent GHD through adulthood (n = 8, 88.9%). Conclusion This study has demonstrated that the use of low-dose rhGH could result in healthy populations achieving optimal FAHs. Patients with MPHD might not require retesting as they were likely to have persistent GHD. The results obtained in this research highlight the benefits of the treatment. This treatment can be applied in resource-limited countries.