Bone Abstracts

Introduction: The utility of the determination of bone turnover markers in the evaluation of fracture risk at the patient level is not well-established. In type 2 diabetes (T2DM) there is an increased risk of fractures despite of higher bone mineral density. A recent study shows that a femoral neck T-score of −2.1 in males and −1.9 in females with T2DM present the same fracture risk than subjects without diabetes with a T-score −2.5 (Schwartz AV JAMA 2011).

Objectives: To evaluate differences in bone turnover in patients with T2DM according to the presence of osteoporosis diagnosed by different classifications.

Methods: Cross-sectional study including 78 T2DM patients. BMD was evaluated by DXA (Hologic QDR 4500). Patients were classified as having or not osteoporosis according to OMS criteria, new criteria from Schwartz et al. and FRAX index.

We determined: bone-specific alkaline phosphatase (BSAP) (OCTEIA™ IDS Ltd Boldon UK), osteocalcin (OC) (DiaSorin, Stillwater, Minnesota USA); TRA5b (Bone TRAP® Assay. IDS Ltd); and CTX (Elecsys β CrossLaps, Roche Diagnostics SL, Barcelona, Spain); results were analysed by SPSS 15.0.

Results: There were no differences in BSAP, OC or TRAP5b according to the three classifications. However, CTX were higher in patients classified as having osteoporosis according the Schwartz criteria, both at femoral neck (0.379±0.173 vs 0.188±0.108 ng/ml, P<0.001) at lumbar spine (0.306±0.170 vs 0.168±0.087 ng/ml, P<0.001), and also in patients selected for treatment by FRAX (0.368±0.114 vs 0.199±0.105 ng/ml, P=0.01). CTX were also higher in patients with osteoporosis by OMS criteria, although only at lumbar spine (0.328±0.182 vs 0.183±0.081 ng/ml, P<0.001).

Conclusions: Our results suggest that higher CTX concentrations may indicate which T2DM patients are suitable for osteoporosis treatment, although CTX does not constitute a fracture risk factor independently of BMD. However, it may help in the identification of patients in whom DXA must be done.