Michihiro Takahashi, Naohiro Nakahara, Shinji Fujikoshi, Masaomi Iyo

To compare the rates of antipsychotic response, remission, and relapse in patients with schizophrenia treated with olanzapine or other antipsychotics in usual clinical care in Japan. This analysis of a 12-month, prospective, noninterventional study examined outcomes for 1,089 inpatients and outpatients with schizophrenia who initiated antipsychotic monotherapy. All treatment decisions, including medication choice, were left to the discretion of the treating physician. The rates of treatment response, relapse, and 6-month sustained remission were compared between olanzapine monotherapy (OLZ) and other anti-psychotic monotherapy (OAN), and between OLZ and other atypical antipsychotic monotherapy (OAT). Visit-wise comparisons of treatment response and remission were examined using repeated-measures logistic regressions. Propensity scores were used to control for potential baseline differences between groups. Response rates were higher for OLZ patients and relapse rates were consistently lower for OLZ patients, however the differences were not statistically significant. Rates of 6-month sustained remission were significantly higher for OLZ than OAN patients (P=0.032) and for OLZ than OAT patients (P=0.041). An exploratory analysis of OLZ and OAN comparison found outpatients treated with OLZ or OAN had similar sustained remission rates (OLZ: 22.2%, OAN: 22.8%), while inpatients treated with OLZ had significantly higher sustained remission rates than inpatients treated with OAN (OLZ: 17.1%, OAN: 6.6%, odds ratio [95% confidence interval] =3.54 [2.00-6.25]). In usual care in Japan, treating the acute symptoms of schizophrenia with olanzapine was not found to be significantly different for response and relapse rates; however, treatment with olanzapine was found to have significantly greater sustained remission rates than treatment with other antipsychotics. In the inpatient setting, where patients tend to be more severe and difficult to manage, olanzapine treatment may lead to higher sustained remission rates than other antipsychotics.