Endocrine Abstracts

Background: Diabetes mellitus is a metabolic disease associated with an increased risk of fracture, despite normal or increased bone mineral density (BMD), especially type 2 diabetes mellitus (T2DM). Trabecular bone score (TBS) is an imaging investigation that measures the grayscale variations on the lumbar spine performed on the DXA machine. The aim of this study was to evaluate the determinants associated with low BMD and TBS in patients with type 1 and type 2 diabetes mellitus.

Methods: We retrospectively analyzed 47 patients with T1DM and T2DM from our clinic between 2015 and 2017. The exclusion criteria were: absence of diabetes, secondary causes for diabetes and age <18 years. We divided the group by T/Z score and TBS and evaluated the predictors for bone structure. To identify the predictors, we performed binary logistic regression. In the multivariate analysis were introduced all the variable with P<0.2 in group comparison. Predictive performances of significant variables were evaluated.

Results: Among the 47 patients, 76.6% had a TBS compatible with altered bone structure, while only 31.9% had a T/Z score diagnostic for osteopenia or osteoporosis. The predominant gender was female (83%), median age was 63 years (IQR: 54–68) and the study group was characterized by overweight (mean BMI=30.5±4.9). The mean duration of DM was 10.9±7.4 years. The majority of patients had type 2 DM (89.4%). By multivariate analysis, β-crosslaps (CTX) was independently associated with a low T/Z score (adjusted OR=1.02; 95% CI: 1.010–1.029, P=0.001). The cut-off value of CTX=0.2915 ng/ml had a sensitivity of 86.7% (95% CI: 59.54–98.34%), specificity of 78.1% (95% CI: 60.03–90.72%) and an AUC of 0.85 (95% CI: 0.72–0.98, P<0.0001) to predict osteopenia or osteoporosis. Also, in multivariate analysis age was independently associated with low TBS (adjusted OR=1.08, 95% CI: 1.01–1.14, P=0.02). The cut-off value of age of 61.5 years had the best predictive performance for altered bone structure, with a sensitivity of 69.4% (95% CI: 51.9–83.6%), a specificity of 72.7% (95% CI: 39–93.98%) and an AUC of 0.73 (95% CI: 0.54–0.91, P=0.02).

Conclusions: Patients with diabetes mellitus showed a more altered bone quality using TBS than DXA and β-crosslaps is an independent predictor for low BMD using DXA, while age is an independent predictor for low spine TBS.