A practical use of bone turnover markers in management of patients with skeletal fragility

Bone turnover markers (BTMs) are metabolites produced during the bone remodeling cycle. BTMs can be distinguished in bone formation (procollagen type I N-terminal propeptide, bone-specific alkaline phosphatase and osteocalcin) and bone resorption markers (C-terminal telopeptide of type 1 collagen, N-terminal telopeptide of type 1 collagen and the tartrate-resistant isoform 5b of acid phosphatase). The evaluation of BTMs can offer dynamic information on bone turnover, making it a valuable tool for the management of patients with bone metabolic diseases.

In the context of osteoporosis, BTMs have demonstrated utility in the monitoring of adherence and response to bone-active treatment, as well as in the management of treatment withdrawal. Additionally, they can be helpful in the evaluation of secondary osteoporosis, mainly when bone turnover is low. However, BTM assessment could be influenced by considerable biological and analytical variability, which must be addressed to ensure a correct clinical interpretation of the values. An accurate patient evaluation is therefore essential for selecting the most reliable biomarker to adopt in clinical practice and appropriate sample handling is critical for minimizing analytical variability.

In recent decades, the applications of BTMs in metabolic bone diseases have expanded significantly and future research will further highlight the role of these markers in the clinical management of osteoporosis.