Long-term bisphosphonate users who switched to the human monoclonal antibody denosumab experienced a gain in hip bone mineral density in the first year of therapy, whereas patients who switched to teriparatide experienced a transient loss in hip BMD, suggesting clinicians should exercise caution when changing osteoporosis agents for patients at high risk for hip fracture, according to a real-world analysis of electronic medical records.

“There is some evidence that prior antiresorptive therapy — in particular, bisphosphonates — may influence the effects of both teriparatide and denosumab,” Houchen Lyu, MD, PhD, a clinical research fellow in the division of rheumatology, immunology and allergy at Brigham and Women’s Hospital in Boston, and colleagues wrote in the study background. “Over 63% of teriparatide users and 54% of denosumab users in the U.S. had been prescribed a prior anti-osteoporosis agent, mostly bisphosphonates. Thus, the therapeutic effect of teriparatide and denosumab in typical clinical practice may not be the same as reported in clinical trials.”