Acute Myocardial Infarction in Medicare Beneficiaries During and After the COVID-19 Pandemic.

Importance: During early months of the COVID-19 pandemic, presentations for acute myocardial infarction (AMI) declined significantly, and outcomes worsened. However, the full extent and long-term sequelae of changes in AMI epidemiology during the pandemic remain uncertain, as does whether these patterns differed by rurality. Objective: To describe the epidemiology of AMI-related hospitalizations, interventions, and outcomes among Medicare beneficiaries throughout the COVID-19 pandemic, focusing on differences in urban and rural populations. Design, Setting, and Participants: This retrospective cohort study included all Medicare fee-for-service beneficiaries with AMI between January 1, 2018, and December 31, 2023, in the analysis. Data were analyzed from March 19 to July 9, 2025. Exposures: Time period (prepandemic [January 1, 2018, to December 31, 2019], pandemic [January 1, 2020, to December 31, 2021], and postpandemic [January 1, 2022, to December 31, 2023]) and beneficiary-level rurality. Main Outcomes and Measures: The primary outcome was in-hospital death, defined as death within 1 day of discharge from the index episode of AMI. Secondary outcomes included death within 90 days of the index admission date and postdischarge outcomes. AMI episodes were defined as any emergency department (ED), observational, or inpatient stay with a primary ST-segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) diagnosis or a primary cardiogenic shock and secondary STEMI or NSTEMI diagnosis. Generalized estimating equations clustering on hospitals were used to compare pandemic and postpandemic outcomes with the prepandemic period, adjusting for beneficiary characteristics. Results: A total of 1 152 851 AMI episodes among 1 032 212 beneficiaries were identified between 2018 and 2023, of which 75.6% were NSTEMI. Most AMI episodes were among male (57.6%) beneficiaries aged 65 to 80 years (56.8%). The unadjusted quarterly incidence of AMI decreased from 17.2 to 13.0 episodes per million beneficiary days at risk (quarter 1 of 2018 to quarter 4 of 2023). In-hospital (adjusted odds ratio [AOR], 1.09; 95% CI, 1.07-1.11]) and 90-day mortality (AOR, 1.10; 95% CI, 1.09-1.12) increased during the pandemic and then returned to baseline or lower (AORs, 0.99 [95% CI, 0.97-1.01] and 0.96 [95% CI, 0.95-0.98], respectively). After the pandemic, beneficiaries were less likely to discharge to a skilled nursing facility (AOR, 0.67; 95% CI, 0.66-0.68), utilize the ED (adjusted incidence rate ratio [AIRR], 0.93; 95% CI, 0.92-0.94), or experience readmission (AIRR, 0.90; 95% CI, 0.90-0.92) within 90 days of their index episode of AMI. Patterns were largely similar by rurality. Conclusions and Relevance: In this retrospective cohort study of fee-for-service Medicare beneficiaries, the incidence of AMI decreased during and after the pandemic. Beneficiaries experienced greater in-hospital and 90-day mortality during the pandemic. After the pandemic, in-hospital and 90-day mortality returned to baseline among micropolitan and rural beneficiaries and was lower than baseline among urban beneficiaries.