A prospective study of body weight and serum leptin levels in patients treated with topiramate

Objectives: We prospectively studied 26 (10 women) patients (age, 37.4 +/- 10.3 years) with different types of refractory focal epilepsy who received topiramate as adjunctive treatment. Methods: Body mass indices (BMI, kg/m(2)) and serum leptin levels (SLL) were investigated at baseline (n = 26) and 9.5 +/- 2.9 (T1; n = 21) and 25.0 +/- 3.5 (T2; n = 18) weeks after initiation of topiramate. Results: We found significant reductions in BMI (TI, -0.4 +/- 0.7; T2, -1.3 +/- 2.1 kg/m(2)) but not in SLL, although a tendency for reduced SLL was observed for women. Serum leptin level changes were mostly within the range between fifth and 95th sex-specific BMI-adjusted reference percentiles. Significant inverse correlations were found between baseline values and changes in both BMI (T2; r = -0.76; P < 0.001) and SLL (T2; r = -0.65; P = 0.003). Patients with BMI of 30.0 kg/m(2) or greater showed the highest weight loss at T2 (-4.8 +/- 3.2 kg/m(2)). Conclusions: Our findings do not provide evidence for a direct causal involvement of leptin in topiramate-related weight loss.