Pro-atrial natriuretic peptide and pro-vasopressin for predicting short-term and long-term survival in community-acquired pneumonia: results from the German Competence Network CAPNETZ

Background Community-acquired pneumonia (CAP) is the most important clinical infection with a high long-term mortality rate. The aim of this study was to evaluate the value of biomarkers for the prediction of short-term and long-term mortality in CAP. Methods A total of 1740 patients of mean +/- SD age 60 +/- 18 years (45% female) with proven CAP were enrolled in the study. Mid-regional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro-atrial vasopressin (CT-proAVP), procalcitonin, C-reactive protein, leucocyte count (WBC) and CRB-65 score were determined on admission. Patients were followed up for 180 days. Results MR-proANP and CT-proAVP levels increased with increasing severity of CAP, classified according to CRB-65 score. In patients who died within 28 and 180 days, median MR-proANP (313.9 vs 80.0 and 277.8 vs 76.0 pmol/l, each p<0.0001) and CT-proAVP (42.6 vs 11.2 and 33.2 vs 10.7 pmol/l, each p<0.0001) levels were significantly higher than the levels in survivors. In receiver operating characteristics analysis for survival at 28 and 180 days, the areas under the curves (AUCs) for CT-proAVP (0.84, 95% CI 0.82 to 0.86 and 0.78, 95% CI 0.76 to 0.80) and MR-proANP (0.81, 95% CI 0.79 to 0.83 and 0.81, 95% CI 0.79 to 0.83) were superior to the AUC of CRB-65 (0.74, 95% CI 0.71 to 0.76 and 0.71, 95% CI 0.69 to 0.74, p<0.05), procalcitonin, C-reactive protein and WBC. In multivariable Cox proportional hazards regression analyses adjusted for comorbidity and pneumonia severity, MR-proANP and CT-proAVP were independent and the strongest predictors of short-term and long-term mortality. Conclusions MR-proANP and CT-proAVP are powerful tools for the prediction of short-term and long-term risk stratification of patients with CAP.