Abstracts

Rationale:
Vitamin D deficiency is common among patients with chronic diseases. Patients with epilepsy taking antiseizure medications (ASMs) are an important cohort of this population. Recent studies have shown up to 54% of epilepsy patients taking enzyme-inducing ASMs and 37% of patients taking non-enzyme inducing ASMs have vitamin D deficiency (Meador et al., Epilepsy Research 2014;108:1352-1356). Low vitamin D has been linked to lower seizure thresholds in animals. Low vitamin D is a risk factor for osteoporosis. Lower bone mineral density has also been reported in patients taking antiseizure medications (Farhat et al., Neurology. 2002;58(9):1348-53). While many have published similar findings, it is not clear whether screening for vitamin D deficiency as a modifiable risk factor in the care of epilepsy patients has become common practice. Our study examined the frequency of Vitamin D testing in patients with epilepsy and the approach to follow up in patients attending outpatient clinics at Stanford Health Care. We compared this to the frequency Vitamin D levels were checked in patients with Multiple Sclerosis (MS), as there is a very well-established linkage between low vitamin D levels and outcomes in Multiple Sclerosis.  
Method:
A retrospective review of patients with epilepsy attending ambulatory subspecialty epilepsy clinic in 1 year (from January through December 2018) at Stanford University was performed. Patients 18 years old or older, who had been diagnosed with epilepsy (and not MS), who were seen by epilepsy providers were included in the epilepsy group. Patients who had been diagnosed with MS (and not epilepsy) seen by an MS provider were included in the MS group. In each group, the following data was extracted from patient charts: age, sex, race, BMI, smoking history, history of taking enzyme inducing AEDs or vitamin D supplement, vitamin D level, and DXA scan history. We included vitamin D levels checked anytime from January 2015 through December 2018 to account for levels checked in the recent past by a provider. Charts were identified using the Stanford Research Repository Cohort Discovery (STARR) Tool, an online tool designed for chart identification and review. Results45% of epilepsy patients (864 out of 1920) and 74.9% of MS patients (809 out of 1080) had their vitamin D level checked and the difference was significant (p< 0.0001). Among epilepsy patients 22.45% had vitamin D deficiency (level < 20 ng/ml (n=194)) and 32.06% had vitamin D insufficiency (level between 20-29 ng/ml (n=277)), resulting in a total of 54.51% (n=471) with values below sufficient levels. In the epilepsy group, the mean ±SD/SE of vitamin D level was 29.85 ± 13.53/0.46 (range:< 8-93) and in the MS group the mean ±SD/SE of vitamin D level was 42.18 ± 20.72/0.73 (range:< 8-162).