Prognostic and stratified value of adrenomedullin in community acquired pneumonia patients in emergency department

Abstract

To evaluate the prognostic and stratified value of adrenomedullin (AM) in community acquired pneumonia (CAP) patients in the emergency department (ED). A prospective observational study was conducted. Adult patients who fulfilled the CAP criteria admitted to the ED of Beijing Chaoyang Hospital from August 2011 to November 2012 were enrolled. Serum AM was detected, pneumonia severity index (PSI) score and CURB-65 score were calculated at enrollment. AM level, PSI and CURB-65 scores were compared between patients with severe CAP (SCAP) and non-SCAP (NSCAP), survivors and non-survivors. The prognostic and stratified value of AM, PSI score and CURB-65 score was assessed by logistic regression analysis and receiver operating characteristic (ROC) curve. 511 CAP patients, including 127 of SCAP, were enrolled. The 28-day mortality of the study was 34.2% (175/511). AM, PSI score and CURB-65 score in SCAP patients were much higher than those in NSCAP patients, and were higher in non-survivors than those in survivors. Using logistic regression analysis, AM and CURB-65 score were independent predictors of SCAP [AM: odds ratio (OR)=1.127, 95% confidence interval (95%CI): 1.096-1.158, P=0.000; CURB-65 score: OR=1.421, 95%CI: 1.072-1.882, P=0.014]. Combination of AM and CURB-65 score [area under ROC curve (AUC): 0.822, 95%CI: 0.781-0.863, P=0.000] improved the accuracy of both AM (AUC: 0.808, 95%CI: 0.766-0.850, P=0.000) and CURB-65 score (AUC: 0.644, 95%CI: 0.590-0.698, P=0.000) in predicting SCAP (sensitivity: 81.1% vs. 75.6%, 70.9%; specificity: 70.1% vs. 72.9%, 52.3%; positive predictive value: 46.6% vs. 48.0%, 33.0%; negative predictive value: 91.7% vs. 90.0%, 84.5%). AM and PSI score were independent predictors of 28-day mortality (AM: OR=1.084, 95%CI: 1.060-1.108, P=0.000; PSI score: OR=1.019, 95%CI: 1.011-1.027, P=0.000). The accuracy of AM (AUC: 0.724, 95%CI: 0.678-0.770, P=0.000) and PSI score (AUC: 0.731, 95%CI: 0.686-0.776, P=0.000) in predicting the risk of 28-day mortality was improved with the combination of AM and PSI score (AUC: 0.803, 95%CI: 0.763-0.843, P=0.000; sensitivity: 78.3% vs. 69.1%, 77.7%; specificity: 70.5% vs. 65.5%, 58.9%; positive predictive value: 56.6% vs. 51.1%, 49.6%; negative predictive value: 85.9% vs. 80.3%, 83.5%). AM is valuable for prognosis and stratification of CAP patients in ED. Combination of AM and CURB-65 score is useful for the diagnosis of SCAP. Combination of AM and PSI score improves the prognostic performance in predicting 28-day mortality.