Abstract Body (Do not enter title and authors here): Introduction
Acute coronary syndrome (ACS) is associated with significant morbidity and mortality. Management of ACS includes percutaneous coronary intervention (PCI) and requires the use of antithrombotic therapy, which increases bleeding risk. Chronic steroid use (CSU) is common for many diseases and is also associated with bleeding risk and impaired wound healing. However, data on outcomes of patients with CSU and AMI are sparse.

Methods
Patients admitted for ACS and managed with PCI from 2014 to 2020 with and without CSU were identified using the National Readmissions Database (NRD). In-hospital outcomes include death, arterial thrombosis (composite of ischemic stroke and arterial thromboembolism), and major bleeding (composite of gastrointestinal, intracranial, or post-procedure bleeding or transfusion). Ninety-day readmission outcomes were cardiovascular (CV)-related, bleeding-related and all-cause. Multivariable logistic or Cox proportional hazards were utilized.

Results
A total of 1,087,357 patients with ACS were included, of whom, 9,864 (0.9%) had CSU. After multivariable adjustment, there was no significant difference in in-hospital mortality (3.1% vs 3.2%; OR 1.09, 95% CI 0.93-1.26) or risk of arterial thrombosis (3.3% vs 2.8%; OR 0.91, 95% CI 0.81-1.02) between patients with and without CSU. CSU was associated with an increased risk of major bleeding events (8.3% vs 6.0%; OR 1.15, 95% CI 1.06-1.25). CSU was associated with a higher risk of CV-related (10.7% vs 7.5%; HR 1.10, 95% CI 1.02-1.18), bleeding-related (2.3% vs 1.2%; HR 1.28, 95% CI 1.09-1.51), and all-cause 90-day readmissions (23.9% vs 14.9%; HR 1.28, 95% CI, 1.22-1.34).

Conclusion
Among patients admitted with ACS who underwent PCI, CSU was associated with increased risk of bleeding during index hospitalization and readmissions for bleeding. Furthermore, CSU was associated with increased risk of 90-day CV and all-cause readmission. Further studies are needed to better characterize this risk.