ABSTRACTDISPARITIES IN THE POST-SURGICAL OUTCOMES OF MEDICAID-INSURED PATIENTS WITH SERIOUS MENTAL ILLNESS: ASSOCIATIONS WITH NURSING RESOURCES Christine Langston J. Margo Brooks Carthon Serious mental illness (SMI) affects approximately 14.1 million U.S. adults and is linked to elevated surgical risks, longer hospital stays (LOS), and higher readmission rates. For Medicaid-insured individuals with SMI these risks are exacerbated by limited access to high-quality care and socioeconomic disadvantage, which may worsen postsurgical outcomes. Despite these concerns, no studies have specifically examined whether Medicaid-insured patients with SMI face higher risks for postsurgical mortality, 30-day readmissions and longer LOS than those insured by other payers. Additionally, despite strong evidence that the quality of nursing care affects postsurgical outcomes, no studies have explored how nursing resources may influence insurance-related postsurgical disparities. The purpose of this study was to address these gaps through a systematic review of existing evidence on healthcare utilization among Medicaid-insured adults with SMI and an examination of how variations in nursing resources influence insurance-related disparities in postsurgical outcomes for patients with SMI. The first paper presents a systematic review of healthcare utilization among Medicaid-insured adults with SMI, highlighting high hospital use and poor access to mental health services, with little attention to nursing interventions. The second and third papers analyze cross-sectional data from 2015–2016 across four states and over 220,000 surgical patients to examine how nurse education and staffing impact postsurgical outcomes. Findings show that a 10% increase in BSN-prepared nurses is linked to an 8% reduction in 30-day readmissions, with greater benefits for Medicaid-insured patients. Overall, a higher proportion of BSN nurses was also associated with shorter in LOS. However, for Medicaid patients, poor staffing and low nurse education were linked to shorter LOS—raising concerns about premature discharge. These results challenge the assumption that shorter LOS is always beneficial and highlight the need to interpret LOS in the context of nursing quality and patient complexity. Overall, this dissertation emphasizes the critical role of nursing resources in reducing disparities for Medicaid-insured surgical patients with SMI and supports policies to improve nurse education and staffing to enhance equity in surgical outcomes.