Clozapine reduces rehospitalization among schizophrenia patients.

A number of studies have reported reduced rehospitalization for patients on clozapine. This article adds to that literature by mining the clozapine database at Hillside Hospital. The sample consisted of 81 schizophrenia patients who entered Hillside on a typical neuroleptic and then had their medication changed to clozapine. We ascertained the number of inpatient hospitalizations before starting clozapine and compared this with the number of hospitalizations after starting clozapine. We also followed an age- and gender-matched comparison group of other schizophrenia patients who entered Hillside at approximately the same time. Results indicate that the mean number of rehospitalizations while on a typical neuroleptic was 2.03 (1.93)/year, whereas it was only .56 (.97/year after the commencement of clozapine treatment; t(80) = 5.78, p < .001. A 95% confidence interval for the superiority of clozapine over standard neuroleptic treatment as measured in rehospitalizations/year is (1.0, 2.0). The decrease in hospitalization rate of .4 (1.6)/year (pre-index date minus post-index date) for the comparison group was also statistically significant [t(80) = 2.3, p < .03]; the 95% confidence interval for this decrease over time is (.1, .8). The pre-post change was much greater for the clozapine patients than comparison patients. A 2 x 2 repeated measures analysis of variance (ANOVA) contrasting the comparison group to the clozapine patients both before and after the index date indicates a significant time by group interaction (F(1.80) = 22.35, p < .001), thus documenting the greater relative decrease in rehospitalization rate in the clozapine group.