Tombini M, et al. - Researchers assessed the serum markers of calcium metabolism among adult patients with epilepsy (PWE) treated with antiepileptic drugs (AEDs) and how vitamin D supplementation impacted seizure frequency. Deficiency of vitamin D was found in PWE. It was determined that the serum levels of 25-hydroxyvitamin D (25[OH]D) were based on the characteristics and length of AED treatment. A reduction of seizure frequency was not achieved through vitamin D administration in drug-resistant epilepsy patients.

Methods

• A comparison was made of the serum levels of calcium, phosphate, intact parathyroid hormone (iPTH) and 25-hydroxyvitamin D (25[OH]D) in 160 PWE on chronic therapy with AEDs and 42 matched controls.
• With regard to different features of epilepsy and treatment, blood concentrations were assessed.
• In a subgroup of 48 drug resistant epileptic patients, the effect of vitamin D supplementation on seizure control was investigated.

Results

• Lower serum levels of 25[OH]D were illustrated in PWE compared to control subjects (p < .001).
• Only 25% of PWE showed normal 25[OH]D levels, while 41.9% presented with a vitamin D failure and 33.1% a vitamin D deficiency (p < .001).
• It was determined that 25[OH]D serum levels depended on treatment duration, number of medications and enzyme-inducing AEDs (p < .001, p < .001, p=.013, respectively).
• Additional detrimental effects on 25[OH]D and calcium serum levels were displayed by polytherapy and enzyme-inducing AEDs.
• It was noted that the administration of vitamin D did not significantly improve seizure control.