Increasing Medicaid Acquisition and Sustainment among the Uninsured - ABSTRACT Uninsured patients are subject to catastrophic health expenditures, have higher rates of mortality, and far more limited access to important healthcare resources (e.g., preventative or specialist care, rehabilitation, mental health) compared to insured patients. Uninsured individuals often defer care until treatment is urgently required, which can lead to debilitating disease, job loss and high medical bills. With more than 70% of uninsured patients unable to pay for their healthcare, U.S. hospitals and states are left to bear the brunt of uncompensated care ($42 billion). Hospital Presumptive Eligibility (HPE), a hospital-based emergency Medicaid program, is a successful solution to these problems. Patients enroll in temporary HPE healthcare coverage (up to 60 days), with an opportunity to sustain insurance by applying for Medicaid full coverage. Although HPE is a national Medicaid requirement, California is among the more inclusive in terms of HPE eligibility. Among the 31 million remaining uninsured Americans, 10% are in California, the world’s 5th largest economy. During our previously funded R21 through the NIMHD, we collaborated with the California Department of Healthcare Services (DHCS) to create an innovative new dataset that tracks HPE enrollees across the state and follows them longitudinally to evaluate for Medicaid sustainment. Over 100,000 previously uninsured Californians enroll in HPE annually, up to 64% of whom sustain Medicaid at six-months. Inpatients, those requiring surgery or post-discharge health services are more likely to sustain insurance, with minority groups less likely to sustain. Across hospitals, Medicaid sustainment ranges from 33-97%. Our preliminary data suggests that patient socio demographics, availability and training of hospital personnel and county-level engagement contribute to success of Medicaid sustainment after HPE enrollment. In response to PAR-20-310, investigation of modifiable predictors of Medicaid sustainment will guide our development of a DHCS, hospital and county-stakeholder informed “best practice” toolkit intervention for dissemination across hospitals, with the goal of increasing reducing insurance-based disparities. We will pursue 3 specific aims: (SA1) quantitatively characterize distribution of sustainment across hospitals and identify patient and hospital-level factors associated with Medicaid sustainment after HPE, (SA2) qualitatively identify hospital and county practices that promote or limit success Medicaid sustainment across diverse settings, and (SA3) develop a stakeholder-informed best practice “toolkit” aimed at increasing Medicaid sustainment across hospitals and counties. Our goal by developing strategies for increasing sustained insurance coverage is to improve access to care, clinical outcomes and financial health among disadvantaged and uninsured patients.