Conference Coverage

Study highlights need to address vitamin D deficiency in epilepsy patients


 

AT AES 2016

– Neurologists and other clinicians ordered vitamin D levels, dual-energy x-ray absorptiometry (DXA) scans, and vitamin D supplementation for epilepsy patients in order to diagnose and prevent vitamin D deficiency and osteopenia, results from a single-center study showed.

Vitamin D deficiency and osteopenia are well described in the literature for patients on enzyme-inducing antiepileptic drugs (EIADs), but no guidelines currently exist for when to order tests or supplementation for patients on EIADs or non–enzyme inducing antiepileptic drugs (NEIADs). “Further studies with larger sample sizes will be helpful in order to establish guidelines for neurologists and other physicians,” Sher Afgan, MD, said in an interview at the annual meeting of the American Epilepsy Society.

Dr. Sher Afgan

Dr. Sher Afgan

In an effort to understand current patterns of diagnosing and preventing or treating vitamin D deficiency and osteopenia to inform future guidelines, Dr. Afgan and his associates evaluated the medical records of patients at Drexel University Medical Center, Philadelphia, who had a diagnosis of epilepsy or seizures, were currently on antiepileptic medications, and whose most recent neurology visit occurred between 2009 and 2015. They reviewed a randomized subset of 190 charts to identify those in which the neurologist had ordered vitamin D levels, DXA scans, or supplementation, or whether the diagnostic tests and supplementation were already ordered by another physician. Of the 190 patients, 102 were on EIADs, and 88 were on NEIADs. Compared with those on NEIADs, those on EIADs were older (a mean age of 55 vs. 49 years, respectively; P = .015), had a higher body mass index (a median of 29 vs. 25.5 kg/m2; P = .006), and were more likely to have generalized epilepsy (62% vs. 46%; P = .02).

Dr. Afgan, a research assistant at Drexel, went on to report that neurologists ordered vitamin D levels in 22% of patients; another 12% had already been ordered by another physician. Neurologists were more likely to order vitamin D levels for patients on EIADs, compared with those on NEIADs (32% vs. 10.4%; P less than .001), and vitamin D levels were more likely to be ordered by either neurologists or other physicians for patients on EIADs, compared with those on NEIADs (41% vs. 26%; P = .02). Neurologists ordered DXA scans in 22% of patients, and more often for those on EIADs, compared with those on NEIADs (33% vs. 10.4%; P less than .001). Similarly, DXA scans were more likely to be ordered by either neurologists or other physicians for patients on EIADs, compared with those on NEIADs (35.3% vs. 18.2%; P = .006). Supplementation was ordered in 23% of patients and was more likely to be ordered by neurologists for patients on EIADs, compared with those on NEIADs (36% vs. 8%; P less than .001).

The researchers also found that neurologists were more likely to order vitamin D levels, DXA scans, and supplements for men on EIADs, compared with women on EIADs (odds ratio, 2.178, P = .03; OR, 2.31, P = .02; OR, 1.87, P = .09, respectively). Generalized epilepsy did not significantly account for increases in ordering vitamin D for EIADs. Median total vitamin D levels were lower in patients on EIADs, compared with those on NEIADs (29 vs. 18 ng/mL; P = .03), but age and body mass index were not different among patients for whom neurologists ordered Vitamin D levels, DXA scans, or supplementation.

Dr. Afgan acknowledged certain limitations of the study, including its retrospective design and small sample size. “Also, type and duration of epilepsy, type and duration of antiepileptic drugs, and comorbidities should be considered in further studies with larger sample sizes,” he said. He reported having no financial disclosures.

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