Bone mineral density measurements by DXA are a key component in managing osteoporosis patients.1 For decades we have known that low bone mineral density values predict increased fracture risk.2,3 Yet, more than 50% of the fractures occur in women who do not have “osteoporosis” by BMD testing.4 As bone strength is determined not only by bone mass, but also by geometry, microstructure and the intrinsic properties of the bone matrix, this observation suggests that in addition to low bone mass, deficits in these other traits may contribute to skeletal fragility.5 Recent technologies allow non-invasive assessment of bone microstructure and bone strength, via finite element analysis.6 Indeed, recent studies indicate that deficits in bone microstructure contribute to skeletal fragility independently of DXA-BMD.7 We have used machine-learning approaches to demonstrate that individuals exhibit different “fragility phenotypes” — some with preserved cortical bone, but trabecular deficits and vice-versa. Recent studies have also demonstrated that bone strength measures from computed tomography (CT) predict fracture as well as, or better than BMD.8,9 Accordingly, opportunistic CT — namely the use of CT scans acquired for other medical reasons — may be an efficient means to identify individuals at high risk for fracture.10 Finally, this presentation will review recent work by the Foundation for the NIH SABRE (Study to Advance BMD as a Regulatory Endpoint) project, which aims to validate total hip BMD as a surrogate endpoint for fracture in order to facilitate future clinical trials in osteoporosis.
SC-AUS-NP-00116 September 2020