Bone turnover markers to monitor oral bisphosphonate therapy

Abstract

Bisphosphonates are widely used as first-line therapy to slow bone loss and decrease fracture risk in postmenopausal women with osteoporosis. Nonadherence to oral bisphosphonates diminishes the benefit of reduced bone loss and fracture risk of these medications. Strategies to enhance osteoporosis monitoring and adherence to therapy are crucial to improve outcomes. Dual-energy x-ray absorptiometry (DXA) is the gold standard for monitoring bone mineral density but is slow to detect change after initiation of oral bisphosphonate therapy. Bone turnover markers (BTMs) are by-products released during bone remodeling and are measurable in blood and urine. We review how the rapid change in BTMs can be a useful short-term tool to monitor the effectiveness of oral bisphosphonate therapy, which may ultimately improve adherence to therapy and outcomes. KEY POINTSOral bisphosphonates slow bone loss and reduce the risk of fracture in postmenopausal women with osteoporosis.Nonadherence to bisphosphonate therapy diminishes the benefits of these medications.BTMs are a simple, low-risk, and convenient way to monitor effectiveness and adherence to oral bisphosphonate therapy in addition to DXA.Bisphosophonates induce a rapid dose-dependent decrease in bone resorption markers, making them an excellent tool to ascertain adherence to and efficacy of oral antiresorptive therapy. REVIEW CME MOC

Clinical use of bone markers: a challenge to variability

“…On another note, liver function may influence CTX, NTX and PINP concentrations, whereas kidney function may affect CTX, NTX and osteocalcin concentrations [ 32 ]. Kidney function also has an impact on monomeric PINP, but not on the intact form.…”

Insight into the potential of bone turnover biomarkers: integration in the management of osteoporosis and chronic kidney disease-associated osteoporosis

“…Given the long skeletal half-life of bisphosphonates, the need for continued treatment of osteoporosis is reviewed after 5 years for oral therapies and after 3 years for intravenous therapies with an improved BMD measurement and the absence of incident fractures [23]. In addition, a break in longterm bisphosphonate treatment may minimize their rare adverse effects, such as atypical femoral fractures and osteonecrosis of the jaw [6,7,20]. The use of BTMs to monitor this offset using the LSC and RI methods was proposed in the TRIO extension study.…”

Making best use of bone turnover markers to monitor oral bisphosphonate therapy

“…As discussed by Ashcherkin and colleagues, 1 BTMs are byproducts of bone remodeling released into the bloodstream. The phrase "bone turnover" encapsulates markers of bone resorption and markers of bone formation.…”

“…In healthy bone, there should be a balance between resorption and formation. Markers of bone resorption are elevated in situations where there is greater bone resorption than bone formation, such as in postmenopausal osteoporosis, although, as Ashcherkin and colleagues point out, 1 an elevated marker of resorption is hardly specifi c for postmenopausal osteoporosis and can be seen in a variety of disease states. The value of these byproducts of osteoclastic activity lies in the observation that bone turnover decreases in response to treatment with antiresorptive agents such as bisphosphonates.…”