Clozapine use in schizophrenia: findings of the Research on Asia Psychotropic Prescription (REAP) studies from 2001 to 2009

Objective: Optimizing treatment and outcomes for people with schizophrenia requires understanding of how evidence-based treatments are utilized. Clozapine is the most effective antipsychotic drug for treatment-refractory schizophrenia, but few studies have investigated trends and patterns of its use over time internationally. This study examined the prescription patterns of clozapine and its demographic and clinical correlates in Asia from 2001 to 2009. Method: Clozapine prescriptions were collected in a sample of 6761 hospitalized schizophrenia patients in nine Asian countries and regions using a standardized protocol and data collection procedure. Results: Overall, the proportion of patients receiving clozapine prescriptions was stable across the three surveys from 2001 to 2009, ranging from 14.5% to 15.9%. However, the rates and patterns observed within different regions and countries at each survey differed considerably. Clozapine use decreased significantly over time in China, while it increased in Korea and Singapore. Multiple logistic regression analysis revealed that patients taking clozapine were significantly younger, had a higher dose of antipsychotic drugs in chlorpromazine equivalents, were more likely to be female, had fewer extrapyramidal symptoms, and had more negative symptoms, admissions and weight gain in the past month than those not receiving clozapine. Conclusion: The variability in overall rates and changes in prescription rates over time in these samples suggest that factors other than psychopharmacological principles play an important role in determining the use of clozapine in schizophrenia in Asia.