Endocrine Abstracts

Introduction: Patients with acromegaly, despite normal or even high bone mineral density (BMD), have prevalent vertebral fractures (VFs). HR-pQCT studies in acromegaly have proposed that impaired trabecular bone microarchitecture possibly plays a role in fragility fracture development. As such, we hypothesized that trabecular bone score (TBS) would be low in patients with acromegaly.

Aim of the study: To compare BMD and TBS in acromegaly patients with and without VFs and healthy controls.

Methods: This cross-sectional study compared patients with acromegaly to age- and BMI-matched healthy controls. Study group was recruited from all acromegaly patients who came to a University Endocrinology clinic for follow-up from 6/2016 – 8/2017 and controls consisting of healthy subjects. In all subjects a single measurement of pituitary axis hormone levels, P1NP,CTx, BMD, (total hip [TH] and lumbar spine [LS]) and trabecular bone score (TBS) was performed. Vertebral fractures were identified by DXA VFA. These images were interpreted by an expert musculoskeletal radiologist (H. Genant) using a semi-quantitative approach.

Results: One-hundred six patients with acromegaly (mean age 56.6 years, mean BMI 30.2 kg/m²) and 104 control subjects (mean age 54.06 years, mean 28.4 BMI kg/m²) were included. There was no difference in TH BMD, CTx and plasma cortisol between study groups. Patients with acromegaly had lower LS BMD (1.002±0.16 vs 1.049±0.15; P<0.05) and TBS (1.19±0.13 vs 1.33±0.14; P<0.0001). higher levels of IGF-1 (244.5±189.2 vs 115.2±37.7 ng/ml; P<0.0001) and P1NP (55.69±34.3 vs 45.47±18.6 ng/l; P<0.05). In total, 13 patients and 4 control subjects had VFs identified using IVA. Among acromegaly patients those with VFs had lower TBS (1.11±0.12 vs 1.20±0.13; P<0.05) and P1NP (32.06±16.9 vs 58.5±34.9 ng/l; P<0.05) levels than non-fractured. No difference in BMD (both measured sites), CTx or IGF-1 was observed.

Conclusions: In this study, acromegaly patients had lower TBS and LS BMD than healthy controls. Additionly, those with VFs had lower TBS, and P1NP, but not BMD (both measured sites) than non-fractured acromegaly subjects. Thus, it could be suggested that VFs in acromegaly subjects are associated with impaired trabecular microarchitecture. We suggest using TBS, rather than BMD, to identify acromegaly patients at high VF risk.