Choice of randomization to clozapine versus other second generation antipsychotics in the CATIE schizophrenia trial

There is evidence to suggest that clozapine is underutilized in treatment-refractory schizophrenia. Data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE), a multi-phase, randomized comparative effectiveness trial for schizophrenia, were used to identify factors associated with choosing randomization to clozapine. Two pathways were available in phase 2 of CATIE: randomization to clozapine or an untried atypical antipsychotic (2E), or randomization to an untried atypical antipsychotic (2T). We examined the proportion of entrants who chose to enter phase 2E due to the lack of efficacy of the phase 1 treatment, along with their demographic and clinical characteristics. Only 31.2% who discontinued phase 1 for lack of efficacy entered phase 2E. In multivariable analysis, males showed significantly increased odds of choosing phase 2E (adjusted odds ratio (AOR) = 2.38; confidence interval (CI) = 1.20, 4.70) as did patients with higher Positive and Negative Syndrome Scale total scores (AOR = 1.01; CI = 1.00, 1.03), more inpatient days (AOR = 1.06; CI = 1.02, 1.10) and more outpatient visits, (AOR = 1.06; CI = 1.02, 1.11). More effort examining the decision-making process of patients and providers is needed in order to increase the utilization of this effective treatment.