Retrospectively analysis data suggest that while the majority of epileptics have no significant worsening in bone mineral density, they maintain an amplified risk of suffering major osteoporotic fractures.
Victor Ferastraoaru, MD
New data from a retrospective analysis suggest that the minority of patients with epilepsy with concurrent bone mineral density (BMD) loss are not being treated well enough and that the oft-used Fracture Risk Assessment Tool (FRAX) may underestimate the risk of bone fractures in this population.
The single-center assessment at Montefiore Medical Center included 81 patients, of which 21% (n = 37) developed new osteopenia or osteoporosis since their first dual‐energy absorptiometry (DXA) scan, with at least 5 years between. Data were collected by Victor Ferastraoaru, MD, assistant professor, Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, and colleagues.
“Despite being routinely screened and frequently treated for bone mineral density loss and fracture prevention, many patients with epilepsy suffered new major osteoporotic fractures,” Ferastraoaru et al. wrote. “This observation is especially important as persons with epilepsy are at high risk for falls and traumas.”
The median time between first and second DXA scans was 9.4 years (range, 5—14.7), and the median age at first scan was 41 years (range, 22–77). At the time of first and second scans, 86.4% (n = 70) and 80.2% (n = 65) of patients, respectively, were taking antiepileptic drugs (AEDs) known to decrease BMD—benzodiazepines, valproic acid, zonisamide, and the enzyme‐inducing AEDs carbamazepine, phenytoin, oxcarbazepine, topiramate, and phenobarbital.
Of the 70 patients who were taking AEDs known to decrease BMD at their first scan, 55.7% (n = 39) were also concurrently being treated for bone loss. Of the total population who were taking bone loss treatment at first scan, 46.9% of patients were only taking calcium and vitamin D, and 11.1% were taking bisphosphonates alone or in combination with calcium and vitamin D. At the time of second scan 76.9% (n = 50) of the 65 patients on AEDs which decrease BMD were also being treated for bone loss. This was reflective of a 21.2% increase.
“Of the 37 patients who had abnormal BMD at their first DXA scan, 89.2% were also taking medications to prevent or treat bone loss. At the second DXA scan, out of 32 patients who took both AEDs known to decrease BMD and had abnormal BMD, at least 87.5% were prescribed bone loss treatment,” Ferastraoaru and colleagues wrote.
Using FRAX estimations based on the first DXA scan, no patients in the cohort had a 10-year risk higher than 20% of developing a major—hip, spine, write, or humeral—osteoporotic fracture, though 13.6% (n = 11) sustained such a fracture after their first scan. This threshold of ≥20% appears to be too high, according to Ferastraoaru et al.
“The FRAX calculator is limited in that it neglects to consider the added risk of fracture for persons who are prone to falling, accidents, or physical injury,” the investigators wrote. “This observation is particularly relevant to patients in our clinic setting, as persons with epilepsy are at high risk for falls and trauma and could explain why the FRAX underestimated the number of patients who would suffer a fracture.”
Based on World Health Organization (WHO) criteria, 54.3% (n = 44) of patients had normal BMD, while 39.5% (n = 32) had osteopenia, and 6.2% (n = 5) had osteoporosis at their first DXA scan. Of those 54.3% with normal BMD at first scan, 81.8% (n = 36) continued to have normal BMD at second scan. Of the patients with osteopenia, 21.8% (n = 7) improved to normal BMD. In total, 50% (n = 16) remained osteopenic, and 80% (n = 4) of those with osteoporosis improved to osteopenia.
At the second DXA scan, 8.8% (n = 3) out of the 34 who were <50 years of age had osteoporosis, and 29.7% (n = 14) out of the 47 patients ≥50 years and older had osteoporosis.
“We recommend that persons with epilepsy who present any evidence of BMD loss should be closely monitored and considered for treatment to prevent further BMD loss and to prevent fractures,” Ferastraoaru et al. concluded. “These findings suggest the need for strict treatment algorithms for persons with epilepsy and any evidence of bone loss. Further studies should evaluate how to account for additional risk factors which are specifically pertinent to persons with epilepsy when using the FRAX calculator in clinical practice.”
Miller AS, Ferastraoaru V, Tabatabaie V, Gitlevich TR, Spiegel R, Haut SR. Are we responding effectively to bone mineral density loss and fracture risks in people with epilepsy? Epilepsia Open. Published online April 6, 2020. Accessed April 17, 2020. doi: 10.1002/epi4.12392