Background: Long standing growth hormone (GH) excess causes the skeletal clinical signs of acromegaly with typical changes in bone geometry including increased cortical bone thickness (CBT). However, a high prevalence and incidence of vertebral fractures has been reported. The aim of this study was to assess the course of cortical bone dimensions in the hip by comparing patients with acromegaly and clinically non-functioning pituitary adenomas (NFPA) at baseline and one year after pituitary surgery (1 year PO).
Patients and methods: Dual energy absorptiometry (DXA) was performed in patients with acromegaly (n=56) and NFPA (n=47). CBT in the femoral neck (CBTneck), calcar (CBTcalcar) and shaft (CBTshaft) were determined by Hip Structural Analysis (HSA). CBT at baseline and the change to 1 year PO were compared. Test results were adjusted for differences in gender distribution, age and gonadal status.
Results: Cortical thickness analyses showed higher values [mm] at baseline in patients with acromegaly compared to NFPA: CBTneck median [25th; 75th] 6.2 [4.7; 8.0] vs. 5.1 [4.1; 6.4] (P=0.006), CBTcalcar 4.8 [4.2, 5.7] vs. 4.0 [3.2, 4.5] (P<0.001), CBTshaft 6.2 [5.1, 7.2] vs. 5.2 [4.6; 6.0], (P=0.003). In acromegaly, GH was correlated with CBTneck (r=0.31, P=0.020), whereas IGF-1 was correlated with CBTcalcar (r=0.39, P=0.003) at baseline. In acromegaly, CBTneck decreased with 11.2%, P=0.002 during follow-up. Finally, the decrease in CBTneck and CBTcalcar in acromegaly was significant compared to NFPA (P=0.023 and P=0.017, respectively).
Conclusions: Previous observations of increased CBT in acromegaly were confirmed with DXA-derived HSA in a large, well defined cohort. The decline in CBT in acromegaly could contribute to the increased fracture risk in acromegaly despite increased bone dimensions and disease control.
18 - 21 May 2019
European Society of Endocrinology