Background: Although there are some existing data describing the usage of topiramate in patients with antipsychotic-induced obesity, study on its comparison with metformin is limited. This study aimed to explore the effectiveness and safety of concomitant topiramate on antipsychotic-induced obesity as well as its comparison with metformin.
Methods: 62 stabilized outpatients with antipsychotic-induced obesity were randomized into the topiramate group and the metformin group with 16-week treatment. The patients' weight, body mass index (BMI), waist-hip ratio, and their side effects were assessed and compared. Intention-to-treat and completer analyses were performed. Meanwhile, covariance analysis was conducted to control the impact of the significant difference in BMI between the two groups.
Results: The two groups had comparable characteristics, though their difference in baseline BMI was significant. (1) Intention-to-treat analyses: the random missing values were replaced using the last observation carried forward method when intention-to-treat analyses were conducted. Compared with the baseline, the weight, BMI, and waist-hip ratio in the topiramate group markedly decreased at each follow-up, whereas, in the metformin group, only waist-hip ratio significantly decreased at 4 weeks after treatment. Compared with the metformin, only weight and BMI in the topiramate group were significantly decreased at week 4 after treatment, and at week 8-16, weight, BMI and waist-hip ratio were remarkably declined. (2) Completer analyses: compared with the baseline, the weight, BMI, and waist-hip ratio in the topiramate group at week 4-16 were markedly decreased, whereas only waist-hip ratio with metformin was significantly decreased at week 4. Compared with the metformin, all BMI with topiramate were markedly decreased at week 4-16. Moreover, its weight and waist-hip ratio also were notably lowered at week 8. No significant differences in adverse events were found between the two groups.
Conclusions: Topiramate, similar to metformin in reducing obesity as previously reported, also significantly reduced body weight, BMI, and waist-hip ratio in patients with antipsychotic-induced obesity and demonstrated well tolerance in psychiatric patients. Trial registration The trial was registered at http://www.chictr.org.cn , and the number was ChiCTR-IPR-17013122.
Keywords: Antipsychotics; Metformin; Obesity; Topiramate.