Prognostic Impact of Cancer in Patients Hospitalized for Acute Myocardial Infarction: A Population-Based Cohort Study

Background: Cancer is common among patients with acute myocardial infarction (AMI) and may influence management and outcomes. The prognostic impact of cancer status (active vs. past) and its anatomical site remains insufficiently defined. We evaluated the association between cancer and short- and long-term outcomes after AMI in a large population cohort. Methods: Using linked administrative databases from Lombardy, Italy, we identified adults with a first AMI hospitalization from 2014 to 2022 (N = 124,403). Patients were categorized by cancer history, cancer status (active vs. past), and cancer site. The primary endpoint was in-hospital mortality; secondary endpoints were 1-year all-cause mortality and 1-year rehospitalization for AMI or acute heart failure (AHF). Multivariable log-binomial, Cox, and Fine&Gray models were applied. Results: Overall, 18,463 (14.8%) had a history of cancer. They were older and had higher comorbidity burden. Cancer history was associated with higher in-hospital mortality (adjusted risk ratio [RR] 1.06, 95% CI 0.99-1.13) and one-year mortality (adjusted hazard ratio [HR] 1.46, 95% CI 1.40-1.52). Active cancer carried the greatest risk (in-hospital RR 1.07, 95% CI 1.00-1.15; 1-year HR 1.60, 95% CI 1.53-1.68), whereas past cancer showed no excess mortality. Site-specific analyses identified lung (one-year HR 2.69, 95% CI 2.15-3.37) and hematological cancers (one-year HR 2.19, 95% CI 1.88-2.56) as highest-risk. Elevated mortality with cancer was consistent in STEMI and NSTEMI. Competing-risk analyses showed a similar risk of rehospitalization among cancer and non-cancer patients. Conclusions: In a real-world, unselected AMI population, cancer worsens short- and long-term survival, especially when active and involving the lungs or the hematopoietic tissues. Incorporating cancer status into AMI risk stratification and strengthening cardio-oncology pathways in acute care are warranted to improve patient outcomes.