Clozapine utilization and outcomes by race in a public mental health system: 1994-2000

Objective: This study aimed to assess racial differences in clozapine prescribing, dosing, symptom presentation and response, and hospitalization status. This study extends previous studies of clozapine by examining patient- and treatment-related factors that may help explain or eliminate reasons for differential prescribing. Method: Clozapine records for 373 white and African American patients with schizophrenia or schizoaffective disorder treated between March 1, 1994, and December 31, 2000, in inpatient mental health facilities in the state of Maryland were examined. Records for this study were derived from 3 state of Maryland databases: the Clozapine Authorization and Monitoring Program, the State of Maryland Antipsychotic Database, and the Health Maintenance Information System Database. Results: A total of 10.3% of African Americans (150/1458) with schizophrenia received clozapine treatment compared with 15.3% of whites (223/1453) (chi(2) = 16.74, df = 1, p <.001) during inpatient treatment in the public mental health system in Maryland. Clozapine doses were lower in African Americans relative to whites (385.3 +/- 200.6 vs. 447.3 +/- 230.3 mg/day) (t = -2.66, df = 366, p = .008). At the time of clozapine initiation, whites had more activating symptoms as measured by the Brief Psychiatric Rating Scale (BPRS) (t = -3.98, df = 301, p <.0001); however, African Americans had significantly greater improvements in BPRS total symptoms (F = 4.80, df = 301, p = .03) and in anxiety/depressive symptoms during I year of treatment with clozapine (F = 10.04, df = 303, p = .002). The estimated rate of hospital discharge was not significantly different for African Americans compared to whites prescribed clozapine (log-rank chi(2) = 0.523, df = 1, p = .470); however, African Americans were more likely than whites to discontinue clozapine during hospitalization (log-rank chi(2) = 4.19, df = 1, p = .041). Conclusion: Our data suggest underutilization of clozapine in African American populations. This racial disparity in clozapine treatment is of special concern because of the favorable outcomes associated with clozapine in treatment-resistant schizophrenia and in the specific benefits observed in African American patients. More research is needed to determine why disparities with clozapine treatment occur and why African Americans may be discontinued from clozapine at a higher rate, despite potential indicators of equal or greater effectiveness among African Americans compared with whites.