Topiramate-induced weight loss depends on level of intellectual disability in patients with epilepsy

Objective: Intellectual disability (ID) is associated with weight gain caused by antiepileptic drugs such as valproic acid. The present study analyzed the relationship between ID and weight loss caused by topiramate (TPM). Methods: Seventy-eight patients with epilepsy (35 women, aged 18 to 70 years) were enrolled in this prospective study. Body weight was measured before and 1, 6, 12, and 18 months after initiation of TPM treatment. Both patients and caregivers were provided information about TPM-related weight loss. The patients were divided into the group with no or mild ID (intelligence quotient > 50) and the group with moderate to profound ID (intelligence quotient ≤ 50). Results: Body weight of both groups significantly decreased until 6 months but stabilized after 12 months. Weight loss at 6, 12, and 18 months was significantly greater in the group with no or mild ID than in the group with moderate to profound ID. Body weight change at 18 months was correlated with intellectual levels (β = 0.274, p = 0.011) and baseline body mass index (β = − 0.322, p = 0.002) by multiple linear regression analysis. Conclusions: The present study suggests that the pattern of weight loss during TPM administration differs according to intellectual levels. Patients with ID maintained their body weight. Weight loss due to TPM might be weakened by caregiver control of food intake or inactivity.