Endocrine Abstracts

Introduction: Skeletal complications are among most persistent and invalidating systemic impacts of acromegaly. Assessment of bone health in acromegaly by dual-X-ray absorptiometry (DXA) alone might be insufficient or even misleading.

Patients and methods: Patients with acromegaly (n=170) were classified as active (n=104), operatively cured (n=34) or medically controlled (n=32). We excluded patients with metabolic bone diseases, thyreotoxicosis, primary hyperparathyroidism, antiresorptive therapy, renal failure and postoperative GH deficiency. A total of 57 males and 113 females were included, 52.8 (22.0–78.5) years old. Serum osteocalcin (OC) and beta-cross-laps (CTx) were analyzed in all patients by Roche ECLIA immunoassay on Cobas Analyzer. Gender, age and menopausal status speciffic reference values for OC and CTx were used. Results were expressed as % of upper limit of normal (ULN). Bone mineral density (BMD) was assessed at L1-L4 and Femoral neck using DXA Hologic Discovery-W-QDR (Apex 2.3.2 software). BMD results were expressed as Z score, accounting for age and gender.

Results: Lumbar spine BMD was normal in all patients and not significantly different in active (Zsc: 0.61±0.13) cured (Zsc: 0.32±0.25) or controlled acromegaly (Zsc: 0.17±0.32). Femoral neck BMD was normal in all patients and not significantly different in active (Zsc: 0.61±0.11) cured (Zsc: 0.59±0.19) or controlled acromegaly (Zsc: 0.49±0.22). OC was significantly elevated (P<0.01) in active acromegaly (1.01±0.06%ULN) compared to cured (0.49±0.05%ULN) or controlled (0.55±0.06%ULN). CTx was significantly elevated (P<0.01) in active acromegaly (1.25±0.09%ULN) compared to cured (0.59±0.08%ULN) or controlled (0.70±0.15%ULN).

Conclusion: Serum markers of bone formation (OC) and resorption (CTx) were significantly elevated in active acromegaly compared to cured or controlled, in a large cohort of patients. Bone mineral density was normal and not different in regard to disease activity. Increased bone turnover may be the cause of structural and biomechanical deterioration leading to vertebral fractures despite preserved BMD.