Significance of bone biomarkers determination in the assessment of fracture risk and response to therapy in patients with osteoporosis

Abstract

Osteoporosis is characterised by reduced bone mineral density (BMD), increased bone fragility and risk of fractures. We investigated clinical significance of bone turnover biomarkers determination for the prediction of fracture risk and response to therapy. We performed three months follow-up study in 48 women with osteoporosis. During the follow-up period 32 patients were on antiresorptive and 16 patients received anabolic therapy. Serum alkaline phosphatase (ALP), osteocalcin, C-terminal telopeptide of collagen type I and vitamin D were measured before and 3 months after initiation of the therapy. Higher osteocalcin and ALP levels were significantly associated with increased risk of BMD loss. Following antiresorptive therapy levels of C-terminal telopeptide (P lt 0.001) and osteocalcin (P lt 0.001) significantly decreased. Anabolic therapy significantly increased osteocalcin (P lt 0.01). At the study entry 25.5% of the patients had optimal levels of 25(OH)D and 17% had severe vitamin D deficiency. Vitamin D supplementation during three months improved vitamin D status of the patients (P lt 0.001). In conclusion, our data indicate that osteocalcin and C-terminal telopeptide determination may be useful for BMD loss prediction and monitoring of osteoporosis therapy. This study confirmed importance of vitamin D testing in osteoporosis in order to detect the patients with deficiency and determine the need for supplementation.

Osteoporoza se karakteriše smanjenom mineralnom gustinom kostiju, što povećava fragilnost kostiju i rizik za nastanak fraktura. U ovoj studiji pratili smo 48 pacijentkinja sa osteoporozom tokom tri meseca sa ciljem da utvrdimo značaj određivanja koštanih biomarkera u proceni rizika od fraktura i praćenju terapije osteoporoze. Tokom trajanja studije 32 pacijentkinje su bile na antiresorptivnoj, a 16 na anaboličkoj terapiji. Svim pacijentkinjama odredili smo aktivnost alkalne fosfataze (ALP) i koncentracije osteokalcina, C-terminalnog telopeptida kolagena tip I i vitamina D u serumu pre i tri meseca nakon uvođenja terapije. Sa povećanjem nivoa osteokalcina i ALP rastao je rizik za smanjenje mineralne gustine kostiju (BMD). Antiresorptivna terapija dovela je do značajnog smanjenja koncentracija C-terminalnog telopeptida (P lt 0,001) i osteokalcina (P lt 0,001). Tokom anaboličke terapije nivo osteokalcina je značajno porastao (P lt 0,01). Na početku studije 25,5% pacijentkinja je imalo optimalne koncentracije 25(OH)D u serumu, a tešku deficijenciju 17% žena. Nakon 3 meseca suplementacije većina je poboljšala status vitamina D (P lt 0,001). Naši rezultati ukazuju da određivanje osteokalcina i C-terminalnog telopeptida može biti korisno za predviđanje rizika za smanjenje BMD i praćenje efekata terapije osteoporoze. Takođe, potvrđena je važnost određivanja koncentracije 25(OH)D za procenu statusa vitamina D u osteoporozi, u cilju otkrivanja pacijenata sa insuficijencijom i utvrđivanja potrebe za suplementacijom.