Imminent fracture risk before and after commencing Anabolic treatment for osteoporosis
Abstract
Introduction: The very high-risk patients remain at a comparatively higher risk of sustaining a subsequent fracture following an initial fragility fracture, with the risk being greatest within the first 1-2 years. The current guidance advocates a “treat-to-target” strategy, recommending initiation of anabolic therapy followed by sequential antiresorptive treatment. The objective of this study was to quantify imminent fracture risk before and after commencing anabolic agents.
Materials and Methods: We conducted a retrospective review of all patients who were commenced anabolic therapy between 2023 and 2025. The study was done at a single centre, the Aneurin Bevan Fracture Liaison Service (AB-FLS). Data collected included patient demographics, fracture type, bone mineral density (T-scores), biochemical markers (serum calcium, alkaline phosphatase (ALP), and 25-hydroxyvitamin D), and average duration of anabolic therapy received. Re-fracture events following the index fracture were recorded both before and after commencement of anabolic therapy.
Results: 168 patients received anabolic drugs (Abaloparatide=56; Romosozumab=60; Teriparatide=52), average age was 70±6.9 years. Nine patients received Abaloparatide for primary fracture prevention.
The average t-scores for spine and femur were -3.1 (-0.1 to –5.5) and -2.7 (-0.3 to –4.6) respectively. Mean Calcium=2.4 (1.31–2.67); ALP=94.2 (44–318); eGFR=70.6 (25–90); PTH=5.7 (1.8–13.1); and Vitamin D was 90.6 (15–281).
The average duration since treatment initiation was 97 days (10-249) for Abaloparatide, 383 days (49-802) for Romosozumab, and 141 days (7-271) for Teriparatide.
No imminent fractures occurred in patients receiving Abaloparatide either before or after treatment initiation. Prior to anabolic therapy, seven imminent fractures occurred in the Romosozumab group, with a mean time of 141 days before treatment initiation (07 to 277 days), and three imminent fractures occurred in the Teriparatide group, with a mean of 117 days before treatment initiation (55 to 231 days).
Following initiation of anabolic therapy, one imminent fracture occurred in the Romosozumab group at 160 days, and two occurred in the Teriparatide group at a mean of 130 days (70–189 days).
Conclusion: In this single-centre cohort of very high–risk patients, 5.9% sustained an imminent fracture while awaiting initiation of anabolic therapy, occurring at a mean of 129 days, and a further 1.8% experienced re-fracture after treatment commencement, at a mean of 145 days. These findings support prudent and timely identification of very high-risk patients and minimising delays in initiating anabolic therapy through targeted quality improvement initiatives.