Plasma Pro-Adrenomedullin But Not Plasma Pro-Endothelin Predicts Survival in Exacerbations of COPD

BackgroundPlasma endothelin and adrenomedullin are increased in patients with pulmonary arterial hypertension, hypoxia, and pulmonary infections, conditions that predict survival in patients with COPD. We investigated whether plasma pro-endothelin-1 (proET-1) and/or pro-adrenomedullin (proADM) on admission to the hospital for acute exacerbation predict survival in patients with COPD.MethodsWe examined 167 patients who had been admitted to the hospital for acute exacerbation, and we followed them up for 2 years. We measured plasma C-terminal (CT) proET-1 and mid-regional (MR) proADM on hospital admission, after 14 to 18 days, and after 6 months. In addition to plasma CT proET-1 and MR proADM, we assessed with Cox regression univariate and multivariate analyses the predictive value of clinical, functional, and laboratory parameters on 2-year survival. We analyzed the time to death by Kaplan-Meier curves.ResultsCompared to recovery and stable state, CT-proET-1 and MR-proADM were significantly increased on hospital admission (p < 0.001 and p = 0.002, respectively). MR-proADM, but not CT-proET-1, was associated with increased in-hospital mortality (p = 0.049) and independently predicted 2-year survival (p = 0.017). ProADM plasma levels > 0.84 nmol/L on hospital admission increased the mortality risk within 2 years from 13 to 32% (p = 0.004). By contrast, age (p = 0.779), Charlson comorbidity score (p = 0.971), body mass index (p = 0.802), FEV1 percent predicted (p = 0.741), PAo2 (p = 0.744), PAco2 (p = 0.284), leukocyte counts (p = 0.333), C-reactive protein (p = 0.772), procalcitonin (p = 0.069), pulmonary arterial hypertension (p = 0.971), and CT-proET-1 (p = 0.223) were not independently associated with 2-year survival.ConclusionsThis study shows that plasma proADM but not plasma proET-1 on admission to the hospital for acute exacerbation independently predicts survival, thus suggesting that this biomarker could be used to predict prognosis in patients with COPD.