Date of Award

2013

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Pharmaceutical Sciences

First Advisor

Stephen Kogut

Abstract

Background: Schizophrenia is a prevalent and costly condition in the United States. Many studies have been conducted on the schizophrenia populations receiving government sponsored insurance, but less is known about the 16% of the population that receives commercial insurance. A better understanding of the utilization and outcomes in this population is essential to ensure that outreach programs target the groups most in need, that these programs are aimed at the most important aspects of utilization, and that those factors are tied to meaningful clinical outcomes.

Objectives: The purpose of this research has been to better understand the patient characteristics, utilization patterns, and outcomes in patients with schizophrenia that participate in commercial insurance plans. Three studies have been completed to address the following specific aims: 1) To describe the schizophrenia population, 2) To determine if the sociodemographic, clinical, and employment characteristics of these patients are associated with their utilization patterns, and 3) To determine if adherence to therapy is associated with the rate of hospitalization for mental health conditions.

Methods:In order to accomplish these goals several studies have been completed utilizing claims data from calendar years 2000 and 2001. The first is a retrospective cohort analysis identifying relationships between utilization of first and second generation antipsychotics, switching between therapies, and combination therapy and patient characteristics; the second study identifies the associations between patient characteristics and adherence; the final study utilizes a retrospective cohort design to determine the association between adherence and hospitalizations.

Results: Patient characteristics are a significant predictor of utilization, with individuals living in the North Central region and individuals with comorbid bipolar disorder significantly more likely to use second generation antipsychotics. Adherence was associated with comorbid diabetes and mental health disorders. Adherence as measured by an MPR greater than or equal to 80% was associated with a lower risk of hospitalization due to mental health conditions.

Conclusion: This series of studies has identified significant associations between comorbidities and increased likelihood to switch medications, utilize a second generation antipsychotic, or combine therapies. Comorbidities also increase the likelihood that someone will not be adherent to their therapy. Low adherence to therapy in turn increases the likelihood of hospitalization.

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