INDEX OF THE OSTEOPOROTIC RISK IN THE EVALUATION OF THE DENOSUMAB TREATMENT

Abstract

Objective. Predomination of bone resorption compared to bone formation in postmenopausal (PM) osteoporotic women and inversion of this relation during denosumab treatment (DT), indicated the need to discover their relationship as an index of the osteoporotic risk (IOR). Osteocalcin and β-CrossLaps (CTX) reduction and IOR increase were determined during one year of DT in order to discover its efficacy. Material and methods. Bone turnover markers N-MID osteocalcin (O) and CTX, expressed in ng/ml, and their ratio IOR=O/CTX were determined during DT in 18 PM women with osteoporosis. The mean value of the percentage of O and CTX reduction and IOR increase from the basal levels during one year of DT were determined. Results. Pretreatment O levels as well as the correspondent CTX levels lowered and IOR levels increased significantly during one year of denosumab treatment (p<0.0001). O% reduction for 12 months was 46.88±22%, CTX% reduction was 78.6±17% and mean IOR% increase was 166.24±118%, confirming bone formation predomination compared to bone resorption that will enable BMD increase. Conclusions. Significant O and O% decrease, highly significant CTX and CTX% decrease, as well as IOR and IOR% significant increase confirmed predominance of bone formation compared to bone resorption, decreased bone turnover, which indicated reduced osteoporotic risk and fracture risk in postmenopausal women as a result of DT. Determination of the relation of the two processes, bone formation and bone resorption through IOR enabled follow up of the osteoporotic risk and the efficacy of the antiresorptive treatment and confirmed very high efficacy of DT in PM osteoporosis.