Outcomes for schizophrenia patients with clozapine treatment: how good does it get?

Abstract

The objective of this study was to describe the extent/change (2000-2004) of clozapine prescribing in schizophrenia in New Zealand and examine the outcomes associated with increasing treatment duration, and vs. those who discontinue clozapine. Consecutive chart reviews were conducted for adult outpatients in Auckland/Northland regions (T1 = 31 March 2000, T2 = 31 October 2001, T3 = 31 March 2003, T4 = 31 October 2004). Data collected included: patient characteristics, social/functional indicators, diagnosis, duration of illness, psychiatric admissions and treatment information (psychotropic medication, dose, route of administration). Between 2000 and 2004, clozapine for schizophrenia increased from 21.0% to 32.8%. Of those prescribed clozapine at T1, 86.1% were engaged with community services at T4 and 93.2% still prescribed clozapine. Continuing clozapine treatment (vs. other treatment) led to a trend to higher rates of regular occupational activity (37% vs. 14.3%) and lower rates of compulsory treatment (25.1% vs. 46.4%) and significantly lower hospitalisation rates (mean = 0.6 vs. mean = 3.1). For those prescribed clozapine at T4, increasing treatment duration (=10 months, 2-3 years, >3 years) led to a trend to higher rates of living independently (18% vs. 29.2% vs. 34%) and regular occupational activity (26.2% vs. 32.6% vs. 37.5%), and significantly reduced compulsory treatment (44.3% vs. 36.9% vs. 28.6%) and hospitalisation rates in the previous 18 months (1.5 vs. 0.5 vs. 0.2). Clozapine use increased significantly over 4.5 years to expected rates of treatment-resistant schizophrenia. Low clozapine discontinuation rates were found and continuing treatment was associated with real-world improvements in functional and clinical outcomes. These findings support the recommendation of prolonged clozapine trials to improve cost-effectiveness in the most seriously unwell schizophrenia patients.