To examine potential differences in efficacy and safety of treatment with olanzapine in patients with schizophrenia of white and black descent.
A post-hoc, pooled analysis of 6 randomized, double-blind trials in the treatment of schizophrenia, schizophreniform disorder, or schizoaffective disorder compared white (N=605) and black (N=375) patients treated with olanzapine (5 to 20 mg/day) for 24 to 28 weeks. Efficacy measurements included the Positive and Negative Syndrome Scale (PANSS) total score; and positive, negative, and general psychopathology scores; and the Clinical Global Impression of Severity (CGI-S) scores at 6 months. Safety measures included differences in the frequencies of adverse events along with measures of extrapyramidal symptoms, weight, glucose, and lipid changes over time.
51% of black patients and 45% of white patients experienced early study discontinuation (P=.133). Of those who discontinued, significantly more white patients experienced psychiatric worsening (P=.002) while significantly more black patients discontinued for reasons other than efficacy or tolerability (P=.014). Discontinuation for intolerability was not different between groups (P=.320). For the estimated change in PANSS total score over 6 months, there was no significant difference in efficacy between white and black patients (P=.928), nor on the estimated PANSS positive (P=.435), negative (P=.756) or general psychopathology (P=.165) scores. Overall, there was no significant difference in the change in CGI-S score between groups from baseline to endpoint (P=.979). Weight change was not significantly different in white and black patients over 6 months (P=.127). However, mean weight change was significantly greater in black versus white patients at Weeks 12 and 20 only (P=.028 and P=.026, respectively). Additionally, a significantly greater percentage of black patients experienced clinically significant weight gain ([greater than or equal to]7%) at anytime compared to white patients (36.1% vs. 30.4%, P=.021). Changes across metabolic parameters (combined fasting and random lipids and glucose) were also not significantly different between groups, with the exception of a greater categorical change in total cholesterol from borderline to high among white subjects and a categorical change from normal to low in high density lipoprotein (HDL) cholesterol among white males.
The findings did not demonstrate overall substantive differences in efficacy or safety between white and black patients diagnosed with schizophrenia or related disorders treated with olanzapine. However, a significantly greater percentage of black patients (36.1%) experienced clinically significant weight gain compared to white patients (30.4%).