Cancer-associated type 2 versus type 1 myocardial infarction: A physiology-driven framework for inpatient risk stratification.

Abstract

e23234 Background: Myocardial injury during cancer hospitalizations is frequently labeled as myocardial infarction, although many events reflect supply demand mismatch rather than plaque rupture. Distinguishing Type 2 from Type 1 myocardial infarction may better inform inpatient triage and prognosis. This study compared the burden and outcomes of Type 2 and Type 1 myocardial infarction in hospitalized oncology populations. Methods: A serial cross-sectional analysis was performed using adult hospitalizations with a principal diagnosis of malignancy in the 2018 to 2022 National Inpatient Sample with discharge-level survey weighting. Type 2 myocardial infarction was identified using ICD-10-CM I24.8 and Type 1 myocardial infarction using I21 to I22. Outcomes included in-hospital mortality, shock, all types (R57*), mechanical ventilation, intensive care unit utilization proxy, length of stay, hospitalization cost, and All Patient Refined Diagnosis Related Group (APR-DRG) severity. Survey-weighted multivariable regression compared Type 2 myocardial infarction only with Type 1 myocardial infarction only, adjusting for demographics, payer, ZIP-code income quartile, admission type, cancer subtype, hospital characteristics, and year. Results: Among 961,848 unweighted cancer hospitalizations representing 4,809,239 admissions nationally, Type 2 myocardial infarction occurred in 0.70% and Type 1 myocardial infarction in 1.03%. Mean APR-DRG severity was lower with Type 2 than with Type 1 myocardial infarction (3.38 vs 3.75). Mortality was 14.2% with Type 2 versus 19.1% with Type 1 myocardial infarction. Type 2 myocardial infarction was associated with lower shock (5.5% vs 9.2%), mechanical ventilation (8.3% vs 13.9%), intensive care unit utilization (11.9% vs 18.7%), and extreme severity (7.4% vs 12.8%), as well as shorter length of stay and lower costs. After weight adjustment, Type 2 myocardial infarction remained associated with lower mortality (adjusted odds ratio 0.68, 95% CI 0.62 to 0.75), shock (adjusted odds ratio 0.60, 95% CI 0.52 to 0.68), intensive care unit utilization (adjusted odds ratio 0.61, 95% CI 0.56 to 0.68), mechanical ventilation (adjusted odds ratio 0.58, 95% CI 0.52 to 0.65), extreme severity (adjusted odds ratio 0.28, 95% CI 0.23 to 0.34), shorter length of stay (β −1.16 days), lower costs (β −$5,601), and lower APR-DRG severity (β −0.37) compared with Type 1 myocardial infarction. Conclusions: Among cancer hospitalizations, Type 2 myocardial infarction represents a meaningful national burden with high morbidity but consistently lower severity, resource utilization, and mortality than Type 1 myocardial infarction. These findings support early identification of Type 2 myocardial infarction among cancer hospitalizations to appropriately guide prognosis and treatment rather than uniform escalation for myocardial injury.