Acromegaly versus hypogonadism: Bone fragility and evaluation.

Introduction: Osteopathy in patients with acromegaly is characterized by increased prevalence of vertebral fragility fractures (VF). However, the diagnostic criteria for osteoporosis are seldomly met in terms of bone mineral density (BMD), as patients with acromegaly frequently present normal BMD for age and gender.

Methodology: We performed a cross-sectional study on 71 patients with acromegaly and 75 patients with hypogonadism. Turnover markers comprised alkaline phosphatase, osteocalcin, the C-terminal telopeptide of type I collagen and total procollagen type-1 amino-terminal propeptide; imaging comprised dual x-ray absorptiometry for BMD, T and Z scores of the lumbar spine, femoral neck and total hip, trabecular bone score (TBS), and x-ray scans of the thoracic and lumbar spine.

Results: Vertebral fractures (VF) in subjects with acromegaly were significantly more frequent than in subjects with hypogonadism, with a prevalence of 29.6% compared to 9.3%. Patients with acromegaly had significantly higher BMD at all skeletal sites but lower TBS than hypogonadal subjects. This difference remained statistically significant after grouping patients with acromegaly according to gonadal status and comparing them with patients with hypogonadism. However, presence of hypogonadism in patients with acromegaly did not influence BMD, TBS or VF prevalence. Moreover, patients with active acromegaly did not have significantly different BMD, TBS and VF prevalence compared to patients with controlled disease. Patients with acromegaly with VF had significantly lower BMD at all skeletal sites than those without VF, but no difference in TBS.

Conclusions: Vertebral fractures are frequent in acromegaly, and are associated with lower BMD but not with TBS. Patients with acromegaly, regardless of gonadal status, have significantly higher BMD but lower TBS than hypogonadal patients. Moreover, disease activity and hypogonadism do not influence BMD, TBS or VF in acromegaly.