Diagnostic and prognostic value of plasma adrenomedullin in COPD exacerbation.

BACKGROUND Adrenomedullin (ADM) is a regulatory peptide with many biological actions, but little is known about its role in patients with COPD exacerbation. The purpose of this study was to evaluate the diagnostic and prognostic value of plasma ADM levels on hospital admission in patients with COPD exacerbation. METHODS Consecutive subjects admitted to the hospital for COPD exacerbation were included and were followed up for 1 y; in addition, subjects with stable COPD from an out-patient clinic and healthy volunteers were recruited as controls. RESULTS Compared with healthy subjects (145 pg/mL [interquartile range {IQR} 103-290 pg/mL]), plasma ADM levels were significantly higher in subjects with COPD exacerbation (270 pg/mL [IQR 170-510 pg/mL], P = .001) and in subjects with stable COPD (400 pg/mL [IQR 210-525 pg/mL], P < .001). In subjects with COPD exacerbation, ADM levels were significantly elevated during exacerbation (560 pg/mL [IQR 495-630 pg/mL]) compared with the recovery phase (470 pg/mL [IQR 393-553 pg/mL], P = .01) and the stable phase (200 pg/mL [IQR 143-308 pg/mL], P < .001). In receiver operating characteristic analysis, in subjects with COPD exacerbation, ADM had high diagnostic accuracy in differentiating between exacerbation and the stable phase (area under the curve 0.97, 95% CI 0.93-1.02, P < .001). In Cox regression analysis, plasma ADM was not independently associated with 1-y survival (P = .97), but it could accurately predicted the need for ICU care (hazard ratio 1.37, 95% CI 1.09-1.72, P = .008). CONCLUSIONS Plasma ADM is a valuable biomarker to confirm COPD exacerbation; furthermore, plasma ADM independently predicts the need of ICU care, although it is not associated with long-term mortality in patients with COPD exacerbation.