Clinical and Pharmacoeconomic Evaluation of Switch to Olanzapine in Veterans with Schizophrenia or Schizoaffective Disorder

Background: Second-generation "atypical" antipsychotics improve the outcome of patients with schizophrenia, although studies of their cost efficacy in comparison to first-generation "conventional" antipsychotics have yielded mixed results. Objectives: This study examines the cost effectiveness outcome of olanzapine treatment in veterans with schizophrenia (n = 22) or schizoaffective disorder (n = 4). Methods: Health-care utilization and costs associated with prospective olanzapine treatment were compared with those of retrospective first-generation neuroleptic treatment in a mirror-image design. Results: The analysis of variance with repeated measures for the Positive and Negative Syndrome Scale (PANSS; n = 22) showed a significant main effect of olanzapine treatment (p < .025), and the effect was of medium-to-large size (eta(2) = .13). The PANSS-positive subscale (p < .005) and the PANSS general subscale (p < .005) significantly decreased, but the PANSS negative subscale did not change. The quality of life survey (n < 21) significantly increased (p < .025), and the effect size was large (eta(2) = .14). For VA outpatient and inpatient care, study patients incurred an average cost difference of $1,289 (NS) and $6,682 (NS), respectively. Combining inpatient and outpatient VA care, patients incurred an annual difference of -$7,971 per patient (NS). These numerically lower costs were due, in part, to a slower growth rate in outpatient encounters (p = .013), lower overall cost per outpatient encounter (p = .008), and a lower overall inpatient encounter rate (p = .005). Conclusions: Olanzapine treatment resulted in improvements in positive and general psychiatric symptoms, as well as quality of life. Negative symptoms did not change significantly. Though not statistically significant, the postbaseline health-care costs and utilization declined. Psychopharmacology Bulletin. 2008; 41(1): 85-98.