MON-787 Beyond DXA: Report of a patient with high bone turnover markers and rapid bone loss

Abstract Disclosure: L.K. Ereifej: None. J. Azocar villalobos: None. L.E. Aguirre: None. E. Lewiecki: None. Introduction: Measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) combined with clinical risk factors is a robust predictor of fracture risk and the need for pharmacologic therapy to reduce fracture risk. However, these static assessments do not reveal the dynamics of bone metabolism and do not predict the rate of bone loss. This is a report of a patient with osteopenia and high bone turnover markers (BTMs) with a rapid rate of bone loss. Case presentation: A 51-year-old woman who had premature menopause at age 41 years was referred by her gastroenterologist for evaluation of persistent elevation of serum alkaline phosphatase (ALP) (248 U/L, normal range 46-116 U/L) and bone specific ALP (29.6 ug/L, normal range 7-24 ug/L), with normal liver enzymes and no evidence of chronic liver or kidney disease. She complained of generalized musculoskeletal pain but was otherwise healthy, with no known fracture. The clinical work-up was significant for high fasting serum C-telopeptide (CTX) (1546 pg./mL) and procollagen type I intact N-terminal propeptide (P1NP) (180 mcg/L) Other lab tests were within normal limits, including TSH, PTH, vitamin D, phosphorus, magnesium, serum calcium, celiac panel, ESR, CRP, ferritin, ANA, and an overnight 1 mg dexamethasone suppression test. A whole-body nuclear bone scan showed no localized increased bone activity. DXA showed osteopenia, with the lowest relevant T-score -2.4 at left 33% radius. FRAX showed low fracture risk, below the treatment threshold. She was managed with non-pharmacologic therapy with plans to return in 2 years for a repeat DXA. The follow-up DXA showed a statistically significant decrease in BMD at left total hip, with the lowest relevant T-score now -3.1 at left 33% radius. Secondary osteoporosis work up was still unremarkable. The patient was then treated with IV zoledronic acid. Six months later there was a substantial reduction of CTX to 485 pg/mL and ALP to 159 U/L. A third DXA 12 months after zoledronic acid showed improvement in BMD by 11% at left total hip with a numerical improvement at the left 33% radius T-score to -2.8. Conclusion: This patient illustrates the association of high BTMs and rapid bone loss, suggested a need for closer observation and perhaps earlier intervention than in patients with lower BTMs.References;Vilaca T, Gossiel F, Eastell R. Bone Turnover Markers: Use in Fracture Prediction. J Clin Densitom. 2017 Jul-Sep;20(3):346-352. doi: 10.1016/j.jocd.2017.06.020. Epub 2017 Jul 14. PMID: 28716498.Bandeira F, Costa AG, Soares Filho MA, Pimentel L, Lima L, Bilezikian JP. Bone markers and osteoporosis therapy. Arq Bras Endocrinol Metabol. 2014 Jul;58(5):504-13. doi: 10.1590/0004-2730000003384. PMID: 25166041. Presentation: Monday, July 14, 2025