SUN-348 Growth Hormone Replacement in Adults During 8 Years Leads to Sustained Increase in Bone Mineral Density

Introduction: Adult growth hormone deficiency (AGHD) is associated with lower bone mass and likely with increased risk of fragility fractures. GH replacement leads to increase in bone mineral density (BMD).However, only few studies longer than 2 years exist. Aim: To assess long-term effect of recombinant GH replacement on BMD and bone turnover markers duringperiod of 8 years. Patients & Methods: Prospective follow-up of all (N=63) AGHD patients at one single center. All patients with adult GHD followed at single center. All participants were replaced with daily injection of recombinant human (rh) GH in IGF-1 normalizing regimen according to Endocrine Society Guidelines. Every 2 years, lumbar spine (L-spine) and total hip (TH) BMD using dual X-ray absorptiometry on Hologic Discovery device, was assessed. All patients were assessed for bone turnover markers; carboxy-terminal collagen crosslinks (CTx) and osteocalcin (OC), and 25(OH)D levels. Deficiencies of other pituitary axes were treated if necessary. All patients were supplemented with 800 IU /day of cholecalciferol and 1000-1200mg/day of calcium as recommended by International Osteoporosis Foundation. Results: Study group consisted of 38 males and 25 females (35 with adult onset (AO) /28 with childhood onset (CO); mean age at diagnosis 25,1 yrs) AGHD patients. All patients ended 8 years follow-up period without any treatment discontinuation during this period. Treatment was well tolerated, without any serious adverse event. IGF-1 has reached the normal ranges during first 6 months and remains normal during whole study period documenting good adherence to treatment (average dose of rhGH=0,4 mg/day). Both, L-spine and TH BMD increased significantly after 8 years of GH replacement (+8 % for L-spine BMD, +7,7% for TH BMD, both p<0,01). The highest peak of BMD was observed after 6 years of treatment. CTx increased by 35% (p<0,05) and remain stable, and no significant change in OC was observed during study period. Levels of 25(OH)D increased by 32% (p<0,05) from baseline. No clinical fractures were observed. Conclusion: Long-term GH replacement in adult GHD together with sufficient levels of vitamin D levels led to increase in BMD and CTx. This study supported fact that GH has sustained effect on bone mass and bone turnover and is safe and well -tolerated for the long time period.