Prevalence, predictors, and in-hospital outcomes of ST-elevation myocardial infarction among young adults without traditional cardiovascular risk factors in the United States

Abstract

Background: Standard Modifiable Cardiovascular Risk Factors (SMuRF) such as hypertension, diabetes mellitus, hypercholesterolemia, and smoking have long been established in the etiology of atherosclerotic disease. Studies suggest that patients without any of these risk factors (SMuRF-less) who present with ST-elevation myocardial infarction have worse outcomes.

Methods: The National Inpatient Sample databases (2016 to 2020) was queried to identify STEMI admissions as a principal diagnosis using ICD 10 codes. The study population aged 18 to 45 years were divided into cohorts of SMuRF and SMuRF-less based on the presence of ≥1 risk factor (hypertension, diabetes mellitus, hyperlipidemia, and smoking), and in-hospital outcomes were compared.

Results: 41,990 patients were identified as the final study population. 38,495 patients were identified as SMuRF, and 3495 patients were SMuRF-less. Compared to SMuRF patients, SMuRF-less patients are more likely to be females (23.2 % vs. 21.2 %), have congestive heart failure (16.6 % vs. 13.7 %, p < 0.01) but less likely to have obesity (13.7 % vs 28.0 %, p < 0.01) In evaluating outcomes, SMuRF-less patients had higher adjusted in-hospital mortality (aOR 2.6, CI 1.5-4.2, p < 0.01), Cardiogenic shock (aOR 1.8, CI 1.3-2.5, p < 0.01), acute kidney injury (aOR 1.4, CI 1.0-1.9, p = 0.02), and Extramembrane Corporeal Oxygenation (aOR 4.1, CI 1.1-15.1, p = 0.03). Fluid and electrolyte abnormalities was an independent predictor of mortality among SMuRF-less patients (aOR 3.82, CI 1.3-11.2, p < 0.01).

Conclusion: Young patients who present with STEMI and have no traditional cardiovascular risk factors have worse in-hospital outcomes. Further research is needed to evaluate the impact of non-traditional risk factors on acute myocardial infarction.