Abstracts

Rationale: Patients with epilepsy (PWE) have a higher fracture risk possibly due to vitamin D deficiency, seizure-related injuries, or anti-epileptic drug therapy (AED) reducing bone mineral density (BMD). Screening of fracture risk in PWE may be necessary at a younger age. Currently, other than Dual-Energy X-Ray Absorptiometry (DXA), there are limited tools available to assess such a risk of fracture. We evaluated the cost-effectiveness of an online assessment tool FRAX in comparison with DXA on screening PWE at high risk of fracture. Methods: We used the online FRAX tool to determine a patient's risk of fracture for the next 10 years. High risk was a FRAX threshold of ≥ 3% for hip and 20% for major osteoporotic fracture (MOF). We surveyed and calculated FRAX scores for 126 patients attending the Robert Wood Johnson outpatient epilepsy clinic. Patients included were age 40-90 years with a diagnosis of epilepsy and currently taking AEDs. We observed the effect of adjusting the FRAX tool by including DXA scans or adding epilepsy as a secondary osteoporosis risk factor. Results: The average FRAX scores for 126 patients with mean age 52.5 years and body mass index (BMI) 28.5 were 4.8% for MOF and 0.7% for hip fracture, and 8 patients (6.4 %) were above treatment threshold. Eighty-four of these patients also had a DXA scan, in which 43 (51.2%) had low BMD (T-score between -1 and -2.5) and of those, 7 (16.2%) had osteoporosis (T-score ≤ -2.5). Two of the 7 osteoporotic patients identified by DXA did not have a FRAX score above threshold even when including BMD or adding epilepsy as a secondary risk factor (Table 1). Of patients with low BMD, 48.8% had poor seizure control, 83.7% were taking AEDs known to reduce BMD, and 65.1% were taking calcium and vitamin D supplements. Based on national osteoporosis guidelines, 8 (9.5%) of the 84 patients with DXA scans were eligible for bone treatment. Thirty patients had a second DXA scan, and 8 (26.7%) experienced an increase in both their lumbar spinal and left femoral neck BMD. All 8 were taking AEDs known to induce low BMD and 87.5% reported at least taking calcium or vitamin D supplements. This is compared to the 22 (73.3%) patients whose BMD declined in the left femoral neck, spine or both, in which 13 (59.1%) were taking medium to high-risk AED's and half were taking calcium or vitamin D supplements. Patients less than 40 years old were excluded, but of those patients (n=93), 8.6% had BMDs below their expected range for age and 7.5% had osteoporosis. Conclusions: More patients were identified for treatment by using the DXA than by using the FRAX tool, even when adjusting for BMD or secondary osteoporosis. Counseling about bone protective behaviors was not a part of this study and more extensive counseling may have resulted in greater improvement in BMD. Patients taking AEDs should be evaluated for DXA screening and counseled about bone protective behaviors as part of routine care. Earlier detection of low BMD allows clinicians to implement bone protective strategies or change high-risk AEDs to minimize fracture risk.