Dissertation Title： "Individual, Clinical, and Contextual Factors Affecting Racial and Ethnic Disparities in Health Care Quality"Current research indicates that there are significant racial and ethnic disparities in the risk factors, incidence, and quality of care for several illnesses, including HIV disease. Although differences in the quality of HIV care are not fully understood, contributing factors may include problems in the physician-patient interaction due to lower trust in physicians among minority patients and racial and ethnic differences in access to facilities that generally provide the best HIV care.

In chapter one, we assessed the relationship between race and trust in four national datasets. In these analyses, only one dataset showed a substantial relationship between race and overall trust in physicians. Important racial differences were, however, found in responses to individual items related to the risk taking behavior of physicians ("risk trust") across datasets, potentially as a result of historic mistreatment of minorities.

In chapter two, we estimated the extent to which risk trust explains racial differences in HIV care. We found that such concerns do not mediate racial disparities in the quality of HIV care, but are an important determinant of adherence to antiretroviral medications. Risk trust not only predicts a patient's belief in the worth of these medications, but it may also have an independent effect on whether the patient is adherent.

Finally, in chapter three we evaluated whether the racial mix of patients at HIV sites of care determines the quality of care and mediates racial and ethnic disparities. We found that as the proportion of black patients at an HIV treatment site increases, the probability that a patient will receive highly active antiretroviral therapy (HAART) decreases after adjustment for patient race, age, gender, and CD4 cell count. However, the racial mix of patients at the site was unrelated to the receipt of HAART after adjustment for a number of other patient characteristics. This suggests that although the receipt of HAART is lower in sites with a high proportion of black patients, this difference is explained by other patient factors.