Risk Factors for Clozapine Discontinuation Among 805 Patients in the VA Hospital System

Abstract

The goal of this study was to determine if demographic or clinical factors collected at baseline on patients treated with clozapine would increase the risk of having clozapine discontinued for (a) lack of response, (b) side effects, (c) noncompliance, (d) concomitant illness, or (e) death. The subjects were 805 patients treated with clozapine at 96 Department of Veterans Affairs Hospital System facilities. Multiple logistic regression was used to determine if any of the baseline variables predisposed patients to discontinuation from treatment. Factors which were studied include age, race, history of inadequate response to traditional neuroleptics, history of substance abuse, and DSM-III-R Axis I diagnosis. Of the 805 patients started on clozapine 167 (20.7%) were discontinued from treatment. The only significant variable in the logistic regression model was race. This study finds that African American patients are more likely to have clozapine discontinued than non-African American patients, and there is a trend for prior history of inadequate response to traditional neuroleptics to predict clozapine discontinuation. We found no effect of substance abuse or dependence, diagnosis, or age on outcome in the overall patient group. In a post hoc analysis the African American patients had a significantly lower baseline white blood count than the non-African American patients, which could have explained the difference in clozapine discontinuation. The findings of this study support further investigation into the causes of ethnic differences in treatment outcome with clozapine.

Racial Disparities in the Use of Second-Generation Antipsychotics for the Treatment of Schizophrenia

“…This finding is not surprising, because previous work has consistently shown that black patients are less likely than white patients to be given a prescription for clozapine and more likely to have clozapine therapy discontinued (10). This finding is not surprising, because previous work has consistently shown that black patients are less likely than white patients to be given a prescription for clozapine and more likely to have clozapine therapy discontinued (10).…”

Outpatient Prescriptions for Atypical Antipsychotics for African Americans, Hispanics, and Whites in the United States

“…It is possible that because of lower baseline white blood cell counts, African Americans may have been subjected to more frequent laboratory testing than whites taking clozapine, adversely affecting patient compliance. 59,60 It is also possible that, because of perceptions of concomitant substance abuse disorders or a history of noncompliance, physicians may have been less likely to prescribe this medication to African Americans and Hispanics. 59 Two studies 59,60 reported that African Americans were more likely to discontinue clozapine therapy than whites, but whether changes in therapy were initiated by the patient or physician was not measured.…”

The Effect of Race-Ethnicity on the Comparative Effectiveness of Clozapine Among Medicaid Beneficiaries

“…It is therefore notable that we did not find racial differences in clozapine’s effectiveness relative to other antipsychotics given evidence that clozapine-treated blacks receive lower doses (17), experience more weight gain (23), and have a higher likelihood of having clozapine unnecessarily discontinued by their physicians (17, 24, 25). …”