Midregional Proatrial Natriuretic Peptide Predicts Survival in Exacerbations of COPD

BackgroundRecently, the use of systemic biomarkers to monitor and assess the clinical evolution of respiratory disease has gained interest. We investigated whether midregional proatrial natriuretic peptide (MR-proANP) predicts survival in patients with COPD when they are admitted to the hospital for exacerbation.MethodsOne hundred sixty-seven patients (mean age 70 years old, 75 men) admitted to the hospital for exacerbation were followed up for 2 years. MR-proANP was measured on admission, after 14 days, and at 6 months. The predictive value of clinical, functional, and laboratory parameters on admission were assessed by Cox regression analyses. The time to death was analyzed by Kaplan-Meier survival curves.ResultsMR-proANP level was significantly higher on admission for exacerbation, compared with recovery and stable state (P = .004 for the comparison among all time points). MR-proANP correlated with the Charlson condition and age-related score (P < .0001), left ventricular ejection fraction (P < .0001), C-reactive protein (P = .037), and FEV1% predicted (P = .004). MR-proANP levels were similar in patients requiring ICU treatment and in those treated in the medical ward (P = .086). Thirty-seven patients (22%) died within 2 years. MR-proANP levels were higher in nonsurvivors compared with survivors (median [interquartile range] 185 pmol/L [110–286] vs 92 pmol/L [56–158], P < .001). Mortality was higher across MR-proANP quartiles (log rank P < .0001). Charlson condition and age-related score (P = .001), Paco2 (P < .0001), and MR-proANP (P = .001) predicted mortality in the univariate Cox-regression model. Both MR-proANP and Paco2 were independent predictors of mortality in the multivariate Cox regression model.ConclusionsMR-proANP at exacerbation is associated with 2-year long-term survival in patients with exacerbation of COPD.