More than 10% of all persons with a SCI/D receive care through the VA and care of Veterans with SCI/D is of central concern to the VA. We have identified that serious morbidities occur following osteoporotic fractures in Veterans with SCI/D. However, there is very little known concerning risk factors for osteoporotic fractures in SCI/D. A better understanding of risk factors for fractures in SCI/D would allow appropriate targeting of existing treatments for osteoporosis. Recently, serious side effects from pharmacological therapies for osteoporosis including osteonecrosis of the jaw and atypical femoral fractures have been reported. Thus, it has now become critically important to avoid overtreatment of patients at low risk for fracture.
Tools which incorporate clinical factors and bone mineral density (BMD) measurements to estimate fracture risk have recently been developed for persons without SCI/D. However, since the pathophysiology of bone loss following SCI/D differs substantially from that of age related, postmenopausal, or even simple disuse osteoporosis, there is a need to develop a distinct model to predict fractures in SCI/D. As a first step towards developing a working model to predict fractures in SCI/D, it is critical to determine whether Dual Energy X-ray Absorptiometry (DXA)-derived BMD is indeed useful for predicting fractures. A second step in developing a working model to predict fractures in SCI/D is to determine which clinical risk factors can predict incident fractures. A final model that can easily identify which patients with SCI/D are at highest risk for fracture that can be used directly in the clinics, would facilitate decision making for clinicians. Such a tool could avoid overtreatment and potential harm to those at low risk for fracture by treatments for osteoporosis, and confer the benefits of such treatments to those who are most likely to fracture. In this context, our working hypothesis is that clinical factors but not DXA-derived BMD will best predict fractures in persons with SCI/D.
Specific Objective 1: Determine the utility of DXA to predict fractures in Veterans with SCI/D.
We hypothesize that DXA-derived BMD will not be able to predict incident fractures in SCI/D. To test our hypothesis, using a retrospective cohort design, we will include Veterans in the SCD Registry in FY2002-2012 and determine whether DXA-derived BMD is able to predict incident fractures during the study period.
Specific Objective 2: Determine the best model for non-axial fracture prediction in Veterans with SCI/D.
We hypothesize that a group of clinical factors will predict incident fractures in SCI/D. To test our hypothesis, we will use a retrospective cohort design, we will include Veterans in the SCD Registry in FY2002-2012 and we will determine which clinical factors can predict risk for incident non-axial fractures through FY2012. Our final fracture prediction model will include BMD (only if BMD can predict fractures) and those clinical risk factors identified to predict incident fractures.
The immediate objectives of this research are to determine whether DXA-derived BMD is a useful tool in predicting fractures in SCI/D and to develop a model to predict fractures in SCI/D. The long-term objectives are to use this model to guide treatment decisions for fracture prevention in Veterans with SCI/D.
This project utilized administrative datasets including the VA Spinal Cord Disorders (SCD) Registry, the DSS Pharmacy and Radiology Systems, the Corporate Data Warehouse and the Austin National Patient Care Databases. In addition, we reviewed DXA scans for a sample of Veterans with SCI/D who had these performed (n=500).
We determined that clinical factors including Caucasian race, Charlson co-morbidity index, prevalent fractures and medication use (heparin, opioids, anticonvulsants, benzodiazepines) were positively related to incident fractures in persons with a SCI. In addition, older women (age 50 and older) were at significantly increased risk for fractures. Use of hydrochlorothiazide was inversely related to incident fractures. SCI-related factors including paraplegia, ASIA A, complete injury and traumatic etiologies of SCI were positively related to incident fracture risk. DXA derived BMD measurements of the lumbar spine and/or hip were not associated with incident fractures in persons with a SCI.
This project has substantial clinical importance. We determined that a set of clinical and SCI-related factors easily elucidated by health care providers can identify which patients with a SCI are at highest risk of fracture.
- Abderhalden L, Weaver FM, Bethel M, Demirtas H, Burns S, Svircev J, Hoenig H, Lyles K, Miskevics S, Carbone LD. Dual-energy X-ray absorptiometry and fracture prediction in patients with spinal cord injuries and disorders. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2017 Mar 1; 28(3):925-934.
- Bethel M, Bailey L, Weaver F, Harmon RL, Priebe MM, Le B, Aslam H, Fausel Z, Hoenig H, Carbone LD. A historical study of appendicular fractures in veterans with traumatic chronic spinal cord injury: 2002-2007. The journal of spinal cord medicine. 2016 Nov 1; 39(6):686-692.
- Bethel M, Bailey L, Weaver F, Le B, Burns SP, Svircev JN, Heggeness MH, Carbone LD. Surgical compared with nonsurgical management of fractures in male veterans with chronic spinal cord injury. Spinal Cord. 2015 May 1; 53(5):402-7.
- Abderhalden L, Weaver FM, Bethel M, Demirtas H, Burns S, Svircev J, Hoenig H, Lyles K, Miskevics S, Carbone LD. Response to Sabour: Dual-energy X-ray absorptiometry and fracture prediction in patients with spinal cord injuries and disorders: methodological issues. [Letter to the Editor]. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2017 Jul 1; 28(7):2261-2262.