12096 Background: ADT is often used with radiation for dose-intensification in intermediate-risk prostate cancer (PrCa). ADT includes gonadotropin-releasing hormone (GnRH) agonists, often started with antiandrogens to prevent the initial surge in serum testosterone as well as GnRH antagonists. Studies have reported associations of ADT with increased risks of cardiovascular events. This is thought to be related to atherosclerosis, dyslipidemia and insulin resistance. Therefore, there is an opportunity to individualize ADT use to balance risk of PrCa specific outcomes with risk of MACE. To address this, we assessed whether there is a difference in major adverse cardiac events (MACE) between ST-ADT ( < 6 months) or LT-ADT ( > 6 months) in patients with localized PrCa. Methods: A nationally representative EHR-derived dataset was queried for patients with at least 90 days of longitudinal records and 90 days of continuous follow up. The inclusion criteria was a diagnosis of PrCa based on standardized diagnoses codes (ICD9 and ICD10). Patients who had a history of MACE (defined as combination of diagnosis and procedure codes associated with CAD, MI, unstable angina, CABG, PCI, catheterization) metastases, PSA above 10ng/mL, imaging for metastatic PrCa, or having received abiraterone or docetaxel within 3 months of inclusion were excluded. Patients were defined as receiving ADT if they received leuprolide, goserelin, bicalutamide, triptorelin, degarelix, flutamide, or nilutamide. The primary outcome of risk of any new MACE was compared between arms with Cox proportional hazards regression. Secondary outcomes including 10 year rates of new diagnoses of CAD, metastases, and new heart procedures were compared between arms with the Chi-square test. Significance was set at a two sided p-value of 0.05. All analyses were performed without matching, with age and gender matching, and high dimensional propensity-score matching (hdPS) using R version 4.05. Results: We identified 1209 patients with local PrCa and no prior MACE or use of abiraterone or docetaxel within 3 months of diagnosis. 385 patients received ST-ADT and 824 received LT-ADT. Baseline characteristics were comparable between the two arms with similar ages, and comorbidity scores. There was no significant difference in metastatic recurrence between arms in hdPS-matched analysis HR 0.95 [0.64-1.38] p = 0.8. There was also no significant difference in the composite endpoint of MACE HR 1.42 [0.86-2.36] p = 0.173. More patients in the LT-ADT arm had new CAD, which was significant after hdPS-matched analysis OR 1.84 [1.07-3.14], p = 0.024. Conclusions: In a national dataset analysis of patients with local PrCa and no history of MACE or abiraterone or docetaxel within 3 months of diagnosis LT-ADT was associated with increased odds of CAD but there was no difference in the composite endpoint of MACE or metastatic recurrence.