Bone Architecture Assessed By Tbs Is Degraded in Patients with Acromegaly

Presentation Number: LB SUN 47
Date of Presentation: April 2nd, 2017

Flávio Moreira Greco Cosso Cosso*1, Paulo Augusto Miranda2, Pedro Weslley Rosario3, Maria Aparecida Moreira Cosso4, Pedro Paulo Martins Alvarenga5, Milena Bellei Leite6, Maria Marta Sarquis Soares7, Antonio Ribeiro Oliveira Junior8, Adriana Maria Kakehasi9 and Barbara C Silva10
1Santa Casa de Belo Horizonte, Belo Horizonte, BRAZIL, 2Santa Casa de Belo Horizonte, Belo Horizonte MG, Brazil, 3Santa Casa de Belo Horizonte, BH, BRAZIL, 4Hospital Madre Teresa, Belo Horizonte, BRAZIL, 5UNI-BH, 6UNIBH, 7Universidade Federal de Minas Gerais, Belo Horizonte MG, Brazil, 8UFMG, Brazil, 9Universidade Federal de Minas Gerais, Belo Horizonte, Brazil, 10Santa Casa de Belo Horizonte


Patients with acromegaly have a higher incidence of fractures than healthy individuals, despite having equal or greater bone mineral density (BMD) than controls. Although high-resolution peripheral quantitative computed tomography (HRpQCT) studies have shown trabecular microarchitectural deterioration in acromegaly, this imaging tool is not widely available in the clinical setting. Trabecular bone score (TBS) is a quantitative estimate of bone architecture, derived from dual-energy X-ray absorptiometry (DXA) images. TBS is associated with fracture risk independent of DXA BMD and clinical risk factors. To this end, we aimed to evaluate TBS in subjects with acromegaly from two referral medical centers.

BMD of the lumbar spine (LS), total femur (TF), and femoral neck (FN) was obtained using a Discovery W scanner (Hologic, software version 3.3.01) in a single center. Site-matched TBS was calculated from LS DXA images using the TBS iNsight software (v2.1). The lowest BMD T- or Z-score was considered for the diagnosis of osteoporosis, osteopenia, low BMD for age or normal BMD. TBS was classified as normal (>1.35), partially degraded (1.20 to 1.35) or degraded (<1.20). The exclusion criteria were a BMI < 15 or > 37kg/m2, use of anti-osteoporotic drugs, presence of CKD, liver disease or other metabolic bone diseases.

We studied 15 patients with acromegaly, including five postmenopausal women and ten men. The mean age was 54±12.5 years, mean BMI 29.4±4.5 kg/m2 and mean time since diagnosis 6.6±7 years. The mean IGF-1 was 1.6±1.1 times the upper limit of normal range (ULN). Among the nine (60%) patients with active disease, the mean IGF-1 was 2.0 times the ULN. While five patients had hypothyroidism, two secondary adrenal insufficiency, and five hypogonadotropic hypogonadism, all patients were on regular hormonal replacement. Patients with adrenal insufficiency were on 2.5mg of prednisone daily. Serum concentrations of free T4, calcium, PTH and creatinine were normal in all participants. The mean 25OH-vitamin D and A1c concentrations were, respectively, 31.3±5.1ng/mL and 6.0±0.6%. The mean TBS was low at 1.209±0.131, while the mean BMD Z-score at the LS, TF and FN were, respectively, +0.6±1.3, +0.2±0.8 and +0.2±0.9. Most (60%) patients had a normal BMD, and 40% had osteopenia. None of the participants had osteoporosis. In marked contrast, TBS was degraded in 46% of patients, partially degraded in another 46%, and normal in only 7% of subjects. While not statically significant, the mean TBS in patients with active acromegaly (1.179±0.122) was lower than in those with controlled disease (1.310±0.158).

Patients with acromegaly have deteriorated bone architecture as assessed by TBS. These results confirm previous findings of lower TBS values in acromegalic patients than in controls, and suggest that TBS may improve fracture risk prediction beyond that provided by DXA BMD in these patients.