Mid-regional pro-adrenomedullin as a prognostic marker in sepsis: an observational study

INTRODUCTION: Measurement of biomarkers is a potential approach to early assessment and prediction of mortality in patients with sepsis. The aim of the present study was to evaluate the prognostic value of mid-regional pro-adrenomedullin (MR-proADM) levels in a cohort of medical intensive care patients and to compare it with other biomarkers and physiological scores. METHOD: We evaluated blood samples from 101 consecutive critically ill patients admitted to the intensive care unit and from 160 age-matched healthy control individuals. The patients had initially been enrolled in a prospective observational study investigating the prognostic value of endocrine dysfunction in critically ill patients ("PEDCRIP" Study). The prognostic value of MR-proADM levels was compared with those of two physiological scores and of various biomarkers (for example C-reactive Protein, IL-6, procalcitonin). MR-proADM was measured in EDTA plasma from all patients using a new sandwich immunoassay. RESULTS: On admission, 53 patients had sepsis, severe sepsis, or septic shock, and 48 had systemic inflammatory response syndrome. Median MR-proADM levels on admission (nmol/l [range]) were 1.1 (0.3-3.7) in patients with systemic inflammatory response syndrome, 1.8 (0.4-5.8) in those with sepsis, 2.3 (1.0-17.6) in those with severe sepsis and 4.5 (0.9-21) in patients with septic shock. In healthy control individuals the median MR-proADM was 0.4 (0.21-0.97). On admission, circulating MR-proADM levels in patients with sepsis, severe sepsis, or septic shock were significantly higher in nonsurvivors (8.5 [0.8-21.0]; P > 0.001) than in survivors (1.7 [0.4-17.6]). In a receiver operating curve analysis of survival of patients with sepsis, the area under the curve (AUC) for MR-proADM was 0.81, which was similar to the AUCs for IL-6, Acute Physiology and Chronic Health Evaluation II score and Simplified Acute Physiology Score II. The prognostic value of MR-proADM was independent of the sepsis classification system used. CONCLUSION: MR-proADM may be helpful in individual risk assessment in septic patients.