Clinical and economic outcomes associated with olanzapine for the treatment of psychotic symptoms in a county mental health population

Abstract

Background: The comparatively high acquisition costs of the newer antipsychotic medications have caused the mental health community to look closely at their potential benefits.Objective: The purpose of this study was to perform a naturalistic analysis of changes in mental health service utilization, economic costs, and clinical outcomes after the initiation of olanzapine therapy for psychotic symptoms in an indigent patient population from a large county-operated mental health care system.Methods: This was a prospective, uncontrolled investigation using a mirror-image cohort design. All captured costs from patients who began olanzapine therapy between November 1, 1996, and April 30, 1998, were analyzed in an intent-to-treat fashion to compare resource utilization in the 12 months immediately before and after the intervention. Clinical function was assessed at baseline and 6 months using the Positive and Negative Syndrome Scale (PANSS). In a subgroup analysis, the baseline characteristics of patients who completed 12 months of olanzapine treatment were compared with those of patients who (1) changed medication or (2) changed payor source or were lost to follow-up.Results: One hundred eighty-nine patients were started on olanzapine treatment during the 18-month study entry phase. Patients were primarily male (63.5%) and had a mean age of 35.9 years. Most (66.3%) had a formal diagnosis of thought disorder. Fifty-six patients received olanzapine for 12 consecutive months, and 22 were switched to other psychotropic medications. Of the remaining 111 patients, 70 changed payors (ie, qualified for Medicaid), and 41 were lost to follow-up. In the subgroup analysis, patients who completed 12 months of treatment (ie, responders) had significantly lower mean PANSS total scores at baseline compared with those who changed payors or were lost to follow-up (P = 0.047), and were significantly more likely to have a formal diagnosis of thought disorder (P = 0.039). Responders demonstrated a significant reduction in PANSS total and negative subscale scores at 6-month follow-up (both measures, P < 0.001). In the intent-to-treat analysis of resource utilization in all patients with complete data sets (n = 78), hospitalization costs and crisis costs decreased significantly during the 12-month follow-up period (P = 0.003 and P = 0.009, respectively), and both outpatient and medication costs increased significantly (P = 0.035 and P < 0.001, respectively). Overall, the change in total annual resource utilization during the 12 months after initiation of olanzapine was not statistically significant (mean decrease per patient, $1991; 95% CI, −$5258 to $1122).Conclusions: Initiation of olanzapine therapy was associated with favorable clinical outcomes in this population, particularly in patients with a formal diagnosis of thought disorder. Overall, there was a cost shift away from hospital and crisis costs toward medication and outpatient services costs. The decline in total resource utilization was not statistically significant, although it may be of practical importance.