2025 Theses Doctoral

The Primary Care Nurse Practitioner Workforce and the Care of Adults with Serious Mental Illness in Socioeconomically Disadvantaged Communities

Dixon, Justinna

Serious Mental Illness (SMI) is defined as mental, behavioral, or emotional disorders that result in serious functional impairments and inhibit one’s ability to perform one or more major life activities. In the United States, approximately 15.4 million people live with SMI, and the care of SMI represents a significant source of economic burden for patients, their families, and society.

Adults with SMI have an increased risk of comorbid chronic conditions, a shorter life expectancy, and higher rates of high-cost, resource-intensive healthcare utilization than the general population. Adults with SMI need comprehensive management of their mental health and physical health conditions; however, many do not receive adequate preventative care or effective management of their conditions, contributing to high rates of emergency department (ED) use and repeated hospitalizations. Mental health provider shortages nationwide have worsened access to effective chronic disease management for adults with SMI, especially in more socioeconomically disadvantaged communities. This has resulted in primary care providers, including nurse practitioners (NPs), filling gaps in care for patients with SMI. Therefore, there is a need to examine the structure of primary care delivery and the role of NP care for this population.

NPs play an important role in providing access to care in socioeconomically disadvantaged communities. As a result of the high-quality care provided by NPs and the increased distribution of NPS in socioeconomically disadvantaged communities, NPs have the ability to address health disparities for adults with SMI. However, NPs often provide care in care environments that are marked by poor organizational support for NP practice and limited comprehension of NPs’ roles. Practices that lack support staff and organizational resources for NPs inhibit NPs from working to their greatest potential and limit their ability to address health disparities.

There is limited evidence to support the role of organizational structure and community-level factors in contributing to outcomes for adults with SMI. Thus, the overall purpose of this dissertation is to produce evidence on primary care delivery for adults with serious mental illness and the role of practice and community-level factors in influencing outcomes for this population.

In chapter 1, we introduced the unique healthcare needs of patients with SMI and the role of community and organizational factors in their health outcomes.

In chapter 2, we synthesized the existing evidence on the impact of various primary care models on emergency department use and hospitalizations among adults with SMI. Our synthesis suggests that models of care that expand the accessibility of primary care, such as the medical home model, are related to reduced acute care utilization among adults with SMI.

In chapter 3, we performed a secondary data analysis using patient data from the Medicare claims of 30,425 adults with SMI, and data from the University of Wisconsin’s Neighborhood Atlas Area Deprivation Index (ADI), which measured community socioeconomic disadvantage. We examined differences in rates of all-cause and preventable ED visits based on the level of community socioeconomic disadvantage. We found greater rates of all-cause and preventable ED utilization among Medicare beneficiaries living in more disadvantaged communities compared to less disadvantaged communities. Our findings suggest that community-level socioeconomic resources play an important role in influencing outcomes for patients with SMI.

In chapter 4, we analyzed patient data from the Medicare claims of 30,425 adults with SMI, merged with NP survey data on NP care environment, and ADI data to assess the effect of the NP care environment on socioeconomic disparities in ED use among patients with SMI. We find that NP care environments moderate the association between community socioeconomic disadvantage and ED utilization (all-cause and preventable). Greater scores in one domain of the NP care environment, support for NP independent practice, was associated with reduced ED utilization in Medicare beneficiaries with SMI. Further analysis found that in more favorable care environments, socioeconomic disparities in ED utilization were mitigated. Our findings provide a modifiable factor—NP care environments, that can be leveraged to reduce socioeconomic disparities and improve outcomes for patients with SMI.

Lastly, in the concluding chapter of this dissertation, Chapter 5, we discuss the strengths, limitations, and contributions of this dissertation. We also present a summary of the findings and implications for policy, practice, and future research.