The impact of antiepileptic therapy on 25(OH)D levels and bone mineral density in epileptic patients

Objective. To investigate the effects of antiepileptic drugs (AEDs) on bone tissue and the laboratory indicators of bone metabolism in patients with epilepsy receiving AEDs for over three years. Material and methods. The study included adult patients of reproductive age with various forms of epilepsy (n=91), categorized into two groups based on treatment regimens: monotherapy and polytherapy. The assessment of 25-hydroxyvitamin D (25(OH)D) levels, serum mineral metabolism indicators, and bone mineral density (BMD) was conducted through X-ray absorptiometry (densitometry), specifically targeting the lumbar spine and proximal femur. Results. The mean 25(OH)D level in the monotherapy group was 27.2 ng/mL versus 22.5 ng/mL in the polytherapy group. A higher prevalence of 25(OH)D deficiency (<20 ng/mL) was observed among patients receiving AED polytherapy (22.2% vs. 11.2% in the monotherapy group). 25(OH)D insufficiency was present at similar rates in both therapy groups, with 16.7% of patients affected in each group. Regression analysis indicated a trend exhibiting a reduction of 7.155 ng/mL in 25(OH)D levels associated with polytherapy. Furthermore, osteopenia or osteoporosis (as indicated by decreased BMD) was identified in 24.6% of the patient cohort; however, no statistically significant correlation was observed between 25(OH)D levels and densitometry findings (p=0.330). Conclusions. The findings suggest that AED polytherapy is associated with lower 25(OH)D levels compared with monotherapy, indicating a cumulative effect of combination therapy on bone metabolism.