THU448 Multiple Non-traumatic Vertebral Fractures After Discontinuation Of Denosumab

Abstract

Abstract Disclosure: S. Riahi: None. A.R. Crawford: None. U. Gruntmanis: None. Background: In multiple studies, including a post-hoc analysis of the FREEDOM trial1, an increased risk of vertebral fractures has been demonstrated in patients after discontinuation of denosumab. Clinical Case: A 65-year-old female presented to the endocrinology clinic for evaluation of severe osteoporosis. She was diagnosed with osteoporosis in 2017 after a DXA scan demonstrated a lumbar spine T-score of −3.5. She was started on denosumab therapy by her primary care provider to treat her osteoporosis and received a total of 10 injections over 5 years, during which time she experienced no fractures. Her lumbar spine T-score improved to −2.6 in March of 2021. She received her last injection of denosumab in December of 2021 and was told that she no longer needed denosumab therapy. She began to develop severe pain in her back in October of 2022 and noticed a 3-inch height loss. X-rays done in November of 2022 demonstrated a new compression fracture in L2. Due to persistent debilitating pain, patient had repeat X-rays performed 1 week later which demonstrated multiple age indeterminate compression fractures which MRI was able to confirm at T5, T7, and T9-T12. Repeat DXA scan in December of 2022 demonstrated a lumbar spine T-score of −3.1. Serum C-Telopeptide (CTX) was 1060pg/mL. Patient had adequate calcium and vitamin D intake, and secondary causes of osteoporosis were excluded. Conclusion: This case report highlights the rapid reversibility of the beneficial effects of denosumab on bone density and bone remodeling after discontinuation of the drug (evidenced by the significantly elevated CTX), the importance of close follow up, and the use of transition therapy in patients after discontinuation of denosumab to attenuate the risks associated with stopping the medication. It also places import on the use of MRI imaging, especially in the cases of rebound associated vertebral fractures secondary to denosumab discontinuation2 for those patients in whom you have high suspicion to better characterize compression fractures when x-ray findings are not felt to be sufficient.