Canadian Study Reveals 10 Years of Insights on Clozapine and Antipsychotics: Relapse and Risks
This Canadian study delves into the real-world effectiveness of clozapine compared to other antipsychotics, focusing on relapse rates and adverse events. Discover how clozapine impacts both adult and child/youth populations, and what this means for clinical decision-making.
Introduction
This Canadian study explores the real-world effectiveness and risks of clozapine, a medication well-regarded for treating treatment-resistant psychoses. By comparing clozapine to other antipsychotics, the research aims to provide insights into its impact on re-hospitalisation rates due to relapse and the incidence of adverse events.
Key Aspects of the Study
Data Sources and Cohorts: Data were sourced from the Canadian Institute of Health Information, covering adults (n = 45,616) and children/youth (n = 1,476) initially hospitalised for mental health conditions in British Columbia, Manitoba, and Saskatchewan from 2008 to 2018. Patient demographics and hospitalisation records were linked with antipsychotic prescriptions dispensed post-initial visit.
Relapse and Adverse Events Analysis: Recurrent events survival analysis was employed to compare relapse and adverse events between clozapine and other antipsychotic medications. The analysis aimed to elucidate the relative risks and benefits associated with clozapine usage in both adult and child/youth populations.
Results
Adult Cohort: Clozapine was associated with a 14% lower rate of relapse compared to other antipsychotics (adjusted hazard ratio: 0.86, 95% CI: 0.83–0.90) over a 10-year follow-up. Initially, the relapse rate was higher for clozapine but improved over time. For every 1,000 person-months, clozapine-treated adults experienced 38 relapse hospitalisations versus 45 for those on other drugs. However, clozapine was linked to a higher risk of adverse events (hazard ratio: 1.34, 95% CI: 1.18–1.54), equating to 1.77 hospitalisations per 1,000 person-months compared to 1.30 for other antipsychotics.
Child/Youth Cohort: Clozapine demonstrated a 38% lower relapse rate compared to other antipsychotics (adjusted hazard ratio: 0.62, 95% CI: 0.49–0.78) throughout the follow-up period. This translates to 29 hospitalisations for clozapine and 48 for other medications per 1,000 person-months. There was no significant difference in adverse events between clozapine and other antipsychotics in this cohort.
Benefits of Clozapine
Reduced Relapse Rates: For both adults and children/youth, clozapine was associated with lower relapse rates compared to other antipsychotics, indicating its superior efficacy in maintaining mental health stability.
Adverse Events Considerations: While clozapine shows promise in reducing relapse rates, it is important to consider the increased risk of adverse events in adults. For children and youth, clozapine maintains lower relapse rates without a higher incidence of adverse events compared to other antipsychotics.
Implementation and Clinical Implications
Clinical Decision-Making: The findings highlight the need for careful consideration of clozapine’s benefits and risks in treatment planning. Clinicians should weigh the lower relapse rates against the potential for increased adverse events in adults and use this information to tailor treatment strategies.
Future Research: Further research is warranted to better understand the long-term benefits and risks of clozapine, particularly in diverse populations and real-world settings, to optimise treatment approaches for psychosis.
Conclusion
Clozapine proves to be effective in reducing relapse rates for both adults and children/youth with treatment-resistant psychoses. However, the increased risk of adverse events in adults necessitates a balanced approach in its clinical use. For children and youth, clozapine offers a valuable treatment option with lower relapse rates and comparable safety to other antipsychotics.
Read more: Clozapine, relapse, and adverse events: a 10-year electronic cohort study in Canada