Routine Troponin I Assessment Enhances Risk Stratification in Hospitalized Patients with Seasonal Influenza

Background/Objectives: Myocardial injury is linked to poor outcomes in respiratory infections. This study evaluated the prognostic value of high-sensitivity troponin I (hsTnI) in predicting 30-day outcomes in patients hospitalized with seasonal influenza. Methods: In this single-center retrospective study, 277 adults with laboratory-confirmed influenza were analyzed. Myocardial injury was defined by elevated hsTnI. The primary composite endpoint included 30-day mortality, intensive care unit (ICU) admission, and mechanical ventilation. Results: Patients with myocardial injury had significantly higher event rates for the composite endpoint than those without (p < 0.0001). Dynamic hsTnI elevations, reflecting acute myocardial injury, were also associated with worse outcomes (p = 0.026). Machine learning models incorporating hsTnI and laboratory data achieved excellent predictive performance (AUC = 0.99) and improved risk classification compared with conventional scores (p < 0.0001). Conclusions: Among hospitalized influenza patients, myocardial injury identified by hsTnI strongly predicted short-term adverse outcomes. Routine hsTnI assessment enhances risk stratification beyond standard clinical scores and may facilitate early identification and management of high-risk patients.