Date of Award

Fall 2017

Document Type


Degree Name

Doctor of Philosophy (PhD)


Health Services Research

Committee Director

Harry Q. Zhang

Committee Member

Martha T. Early

Committee Member

Carolyn M. Rutledge


Depression is the leading cause of disability worldwide, disproportionately affecting the Medicaid population. Collaborative care programs for depression are transforming primary care to increase access and coordinate physical and behavioral health services. Understanding the relationships between components of collaborative care programs, characteristics of participants, and their effect on outcomes can maximize program effectiveness.

A pilot collaborative care for depression program within a Medicaid managed care organization was evaluated using administrative claims and case management data. Participants (n=444) included adults with prior Medicaid coverage and a comparison group identified using one-to-one propensity score-matching. Multivariate logistic regression models estimated the odds of decreases in depression severity and acute care, and increases in outpatient services. T-tests and chi-squares were used to identify factors influencing clinical improvement in depression.

After controlling for covariates, group status was not a significant predictor of the odds of increased health services use. Increased comorbidities was a significant predictor of increased outpatient physical health visits (OR=1.32, 95% CI [0.57,1.06]). Among intervention participants (n=234), significant individual and social determinants of health leading to higher odds of decreased depression and changes in health services use were identified. Additionally, lower illness severity was associated with clinical improvement in depression, t(45.47)=2.60, p