Weight gain with clozapine: 8-year cohort naturalistic study among hospitalized Chinese schizophrenia patients

Objective: Clozapine is associated with significant weight gain. However, it is still debatable whether the majority of weight gain occurs in the early phase of treatment or if weight gain is a persistent side effect. The inconsistent results in previous outpatient studies may be due to many confounding factors, such as variations in drug adherence, diet content, activity level and environmental factors. The objective of this study was to investigate long-term weight changes in hospitalized Chinese schizophrenic patients treated with clozapine. Methods: Patients were admitted at the largest mental hospital in Taiwan and had routine monthly body weight monitoring during the study period. Retrospective chart reviews were conducted to obtain demographic data, age at which clozapine treatment was initiated, and weight changes after the initiation of clozapine treatment. Results: The study sample consisted of 349 hospitalized schizophrenic patients, including 204 males (58.8%), with an average age at clozapine initiation of 38.6 +/- 9.3 and an average clozapine dosage of 318 9.3 mg/day. Body weight increased over time, and reached a plateau at month 42. Younger age at clozapine initiation (P=0.0038) and lower baseline body mass index (BBMI) (P<0.0001) were associated with more weight gain. The patients with BBMI<25 gained significantly more weight (10.98 +/- 8.48 kg) compared to patients with BBMI >= 25 (1.17 +/- 13.29 kg) (P=0.004). Conclusions: Similar to reports on Caucasians, clozapine-associated weight gain in Chinese patients reached a plateau at month 42. Younger patients with normal BBMI were associated with higher risk of weight gain. (C) 2008 Elsevier B.V. All rights reserved.