Prognostic value of cardiac troponin I in hospitalized patients with community-acquired pneumonia: A retrospective cohort study

Cardiac involvement is increasingly recognized in patients with community-acquired pneumonia (CAP). This study aimed to investigate the association between baseline troponin I levels and clinical outcomes, including overall survival, among hospitalized patients with CAP who underwent clinician-directed cardiac evaluation. In this retrospective cohort study, 491 patients were stratified according to baseline cardiac troponin I level (<19.8 ng/L vs ≥19.8 ng/L). Demographic characteristics, comorbidities, laboratory and echocardiographic findings, and clinical outcomes were compared between groups. Survival was analyzed using Kaplan-Meier methods and Cox proportional hazards regression. The median age was 67 years, and 66% were male. Elevated troponin I was detected in 140 patients (28.5%) who were older and had higher rates of coronary artery disease, congestive heart failure, and chronic renal failure, as well as higher Charlson Comorbidity Index (CCI) and Pneumonia Severity Index scores (all P < .05). These patients also had lower left ventricular ejection fraction, higher rates of intensive care unit admission, and in-hospital mortality. During a median follow-up of 439 days, 167 patients (34%) died. Kaplan-Meier analysis showed significantly reduced overall survival in patients with elevated troponin I levels (log-rank P < .001). In multivariate Cox regression analysis, male gender, elevated troponin I (hazard ratio [HR] = 2.016), higher CCI (HR = 1.275), increased blood urea nitrogen to albumin ratio (HR = 2.876), lower hemoglobin levels (HR = 0.841), and reduced ejection fraction (HR = 0.964) were independently associated with mortality. Elevated baseline troponin I was associated with increased mortality and reduced overall survival in this selected high-risk patient population. However, its discriminative performance for mortality was modest (area under the curve [AUC] = 0.64) and lower than that of CCI (AUC = 0.73). The addition of troponin I to a model including age and CCI resulted in only minimal improvement in discrimination (AUC 0.721 vs 0.724), indicating limited incremental prognostic value beyond established risk indices.