Treatment of acromegaly increases BMD but reduces trabecular bone score: a longitudinal study

Bone turnover is increased in acromegaly. Despite normalization of bone turnover after treatment, the risk for vertebral fractures remains increased. Gonadal status, but not BMD, is correlated with vertebral fractures. Trabecular bone score (TBS) is related to bone microarchitecture.

The aim of this study is to assess the longitudinal change in TBS and BMD following treatment for acromegaly. DESIGN, SETTING, PATIENTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: This longitudinal study included 48 patients with acromegaly between 2005 and 2015. BMD, TBS, and markers for bone turnover (P1NP and CTX-1) were measured at baseline and following treatment.

Following treatment, the mean TBS decreased by 3.0 (±7.0) %, whereas the BMD at the lumbar spine (LS) increased by 3.2 (±4.9) % (both P<0.01). The changes in BMD LS and TBS were not correlated (P=0.87). The TBS change was found to be -4.5 % (±6.7; P=0.003) in men and -0.3 % (±6.8; P=0.85) in women (P=0.063 for interaction men vs women). The mean BMD LS increased in men +4.2 g/cm(2) (±4.3; P<0.001), but not in women +1.5 g/cm(2) (±5.6; P=0.36); (P=0.073 for interaction). BMD increased in the ultradistal radius and total body (both P<0.01). The increase in BMD LS was associated with a decrease in P1NP and CTX-1 (P<0.001) and with lower P1NP and CTX-1 at the follow-up (P<0.02).

Treatment of acromegaly affects TBS and BMD at LS in different manners. The reduction of bone turnover markers predicts the increase in BMD but not the decrease in TBS. The DXA changes were more pronounced in men. Alterations in trabecular bone architecture may explain the persistent fracture risk despite the increase in BMD after disease control.