Pro-adrenomedullin to predict severity and outcome in community-acquired pneumonia [ISRCTN04176397]

TLDR: ProADM, as a novel biomarker, is a useful tool for the risk stratification of patients with CAP, and increased with increasing severity of CAP.

Abstract: Pro-adrenomedullin (proADM) is helpful for individual risk assessment and outcome prediction in sepsis. A major cause of sepsis is community-acquired pneumonia (CAP). The aim of this study was to investigate the value of proADM levels for severity assessment and outcome prediction in CAP. Data from 302 patients admitted to the emergency department with CAP were included in a prospective observational study. Procalcitonin, C-reactive protein levels, leukocyte count, clinical variables and the pneumonia severity index (PSI) were measured. ProADM levels were measured with a new sandwich immunoassay for mid regional ProADM (MR-proADM, Brahms AG, Hennigsdorf/Berlin, Germany). ProADM levels, in contrast to C-reactive protein and leukocyte count, increased with increasing severity of CAP, classified according to the PSI score (ANOVA, p < 0.001). In patients who died during follow-up, proADM levels on admission were significantly higher compared to levels in survivors (2.1 (1.5 to 3.0) versus 1.0 (0.6 to 1.6) nmol/l, p < 0.001). In a receiver operating characteristic (ROC) analysis for survival, the area under the ROC curve (AUC) for proADM was 0.76 (95% confidence interval (CI) 0.71–0.81), which was significantly higher compared to procalcitonin (p = 0.004), C-reactive protein (p < 0.001) and total leukocyte count (p = 0.001) and similar to the AUC of the PSI (0.73, p = 0.54). A clinical model including the PSI and proADM increased the prognostic accuracy to predict failure compared to a model relying on the PSI alone (AUC, 0.77 (0.70 to 0.84), p = 0.03). ProADM, as a novel biomarker, is a useful tool for the risk stratification of patients with CAP.