Researchers from the University of California, San Francisco, have concluded that follow-up measurements of bone mineral density (BMD) and bone turnover markers (BTM) are not significant predictors of subsequent vertebral fracture risk in patients who have stopped taking bisphosphonates.
The investigators evaluated the predictive value of BMD and BTM in patients (all women; n=437) who were rerandomized to a drug holiday period of 5 years in the FLEX study (Long-term Extension of FIT [Fracture Intervention Trial]). Their findings were presented during the World Congress on Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases, March 23-26, 2017, in Florence, Italy.
The researchers analyzed data recorded during the trial to measure 1- and 3-year follow-up changes in hip BMD or BTM to determine whether either could be of value as a predictor of any incident vertebral fractures (morphometric or clinical) over the course of 5 years.
Although BMD significantly predicted incident vertebral fracture risk after patients stopped taking alendronate (P <.05), the investigators noted that 1- and 3-year follow-up changes in BMD or BTM after alendronate was discontinued did not significantly predict 5-year risk for vertebral fracture. They noted that the 1-year percentage change in total BMD did not prove to be a significant risk predictor for incident vertebral fracture (odds ratio, 1.1 per 1% decrease; P =.11).
“Follow-up measurements of BMD or BTM after 1 or 3 years of BP discontinuation are not associated with vertebral fracture risk after adjusting for baseline measurements, prevalent vertebral fractures and age,” Change and colleagues wrote in their analysis. “These results suggest that these follow-up measurements are of little clinical utility during a drug holiday after 5 years of alendronate.
Chang S, Bauer D, Black D. Change in bone mineral density (BMD) or bone turnover markers (BTM) did not predict risk of vertebral fracture after discontinuation of alendronate in the FLEX study. Presented at: World Congress on Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases; March 23-26, 2017; Florence, Italy.