Associations of overweight and obesity with drug-resistant epilepsy

Obesity and overweight have been well established as comorbidities of epilepsy in adults. However, the effects of overweight and obesity on the risk of adult drug-resistant epilepsy (DRE) has not been fully assessed. Thus, the objective of this study was to investigate the relationships between categories of body mass index (BMI) and DRE.

This was a case-control study. Patients with epilepsy hospitalized for Video electroencephalogram were included in the study from 2015 to 2020. Low/normal weight, overweight, and obesity were defined as BMI<23 and 23-24.9 and ≥25 kg/m², respectively. The proportions of patients diagnosed with DRE in each category were calculated.

A total of 1272 patients with drug-responsive epilepsy and 345 patients with DRE were included in this study. More men than women had DRE (P=0.012). Higher proportions of patients with DRE had a history of status epilepticus (P<0.001), CNS infection (P=0.027), developmental delay (P=0.001), and comorbidity (P<0.001). Obesity (BMI≥25 kg/m²) was associated with an increased risk of DRE (adjusted OR, 2.339; 95% CI, 1.724-3.171). No significant increase in the risk of DRE was found to be associated with overweight. Further stratified analyses by valproic acid (VPA) treatment attenuated the obesity-DRE relationship, but the associations remained statistically significant (adjusted OR, 1.79; 95% CI, 1.15-2.80).

Obesity, but not overweight, potentially plays a role in DRE, although confounders, such as antiseizure medications (ASMs) use, need to be explored. In the future, well-designed trials are needed to elucidate this issue.