PROJECT ABSTRACT This K23 award will enable the candidate, Shih-Chuan Chou, MD, MPH, SM, to become an independent physician-scientist focused on the effect of out-of-pocket costs on care utilization and outcomes of acute chest pain and cardiovascular care. Chest pain is one of the most common reasons for emergency department (ED) evaluation, with over 7 million visits annually. ED visits ensure the timely identification and treatment of acute myocardial infarction (AMI) or acute coronary syndrome (ACS). However, the financial implications of care have escalated over the past two decades with the growth of high deductible health plans (HDHP). By 2020, nearly 6 in 10 US employees with employer-sponsored insurance will have deductibles of ≥$1,000. While research has begun to explore HDHP’s effect on cancer screening and chronic disease management, little research has examined how it affects acute cardiovascular care. In a preliminary study, Dr. Chou found that HDHP enrollment reduced ED visits for non-specific chest pain but increased AMI after chest pain admission among the lower-income population. In this K23, Dr. Chou will further extend this research with 3 proposed aims. Aim 1 will use segmented survival analysis in a large commercial claims database to examine whether employer-mandated HDHP enrollment negatively impacted AMI outcomes. Using the same database, aim 2 will utilize the natural randomization of patients to ED clinicians within each ED to determine whether HDHP reduces low-value chest pain admissions among clinicians with high admitting tendencies. Lastly, aim 3 will include patient surveys and interviews to elicit chest pain and AMI patients’ perspectives on how high out-of- pocket costs affected their decisions to seek care, perceived care quality, and subsequent financial impact. All aims will further focus on low-income patients that face disproportionate financial stress. Dr. Chou proposed a comprehensive career development curriculum to complement these aims, consisting of extensive didactic and experiential learning. Dr. Chou has assembled an interdisciplinary team of mentors with recognized expertise in quasi-experimental observational studies, insurance benefit design, cardiovascular emergencies, health care disparities, and emergency medicine, who will provide him with intensive mentorship in these topics. The proposed research and career development activities will allow Dr. Chou to establish his expertise in insurance-related policies, the financial burden of care, and their impact on the use and outcomes of patients with acute cardiovascular conditions. This award will enable Dr. Chou to transition into an independent clinician-scientist focusing on the short- and long-term impact of high out-of-pocket costs and the implications around the growing implementation of price transparency and cost discussions for acute unscheduled care visits. Completing the proposed research will generate robust evidence to advance the understanding of the clinical impact of patient financial burden, guide future regulations around insurance cost-sharing policies, and inform the implementation of price transparency initiatives in acute cardiovascular care.

PROJECT NARRATIVE Most US employees have health insurance with greater than $1,000 deductibles, yet little research has studied how high out-of-pocket costs affect patients experiencing acute cardiovascular emergencies such as heart attacks. The proposed research will advance our understanding of high-deductible health plans’ impact on outcomes from heart attacks, unnecessary hospitalizations for chest pain, and patients’ perspectives on how high out-of-pocket costs influence their care decisions and perceived care quality. Results from these studies will provide important implications for future insurance regulations to minimize unintended harm, reduce the financial burden of care, and align clinical decisions with patients’ value perspectives.