Background: People with schizophrenia have a 15–20-year reduction in life expectancy, driven in part by the metabolic effects of antipsychotics. Clozapine is associated with the highest rates of weight gain. As clozapine remains the most effective antipsychotic for treatment-resistant schizophrenia (TRS), identifying treatments to ameliorate clozapine-induced weight gain (CIWG) is urgently needed to reduce this morality gap. Methods: We retrospectively analysed digital health records of patients with TRS aged 18–65 newly initiated on clozapine at four tertiary hospitals in south-east Queensland from 1 March 2017 to 30 June 2019. Our primary outcome was the effect of metformin on change in percentage bodyweight at 12 months after clozapine initiation, with secondary outcome being proportion with >5% or >7% bodyweight change. We also explored impact on bodyweight change of other variables including sex, tobacco smoking, type 2 diabetes (T2DM), age, clozapine level and dose and clozapine/norclozapine ratio. Results: Among 90 patients initiated on clozapine, metformin use ( n = 48) was associated with a smaller increase in percentage bodyweight (1.32% versus 5.95%, p = 0.031), lower rates of >7% gain in bodyweight (37.8% versus 63.0%, p = 0.025) but not >5% gain in bodyweight. Age below the median (32.0 years) was associated with greater bodyweight gain (5.55% versus 1.22%, p = 0.046). Sex, tobacco smoking, T2DM, clozapine dose and level and clozapine/norclozapine ratio were not associated with differences in change in bodyweight. Conclusion: In this small retrospective cohort study, use of metformin within 12-months of clozapine initiation was associated with a statistically and clinically significant reduction in CIWG. Although there is increasing evidence for the role of metformin to ameliorate bodyweight gain at time of clozapine initiation, our findings need replication and testing in a randomised controlled trial before recommending metformin co-commencement with clozapine as standard clinical practice.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.