Pro-atrial natriuretic peptide and pro-vasopressin to predict severity and prognosis in community-acquired pneumonia

Objective: Community acquired pneumonia (CAP) is the most important clinical infection. Therefore, the CAP competence network CAPNETZ was instituted in Germany. The aim of this substudy was to evaluate the value of pro-atrial natriuretic peptide (MR-proANP) and pro-vasopressin (CT-proAVP) for severity assessment and outcome prediction in CAP. Design: Prospective observational study. Setting: German CAP competence network CAPNETZ. Methods: We enrolled 589 patients (age 61 +/- 18 years, 46% female) with proven CAP. MR-proANP, CT-proAVP, C-reactive protein (CRP), procalcitonin (PCT) and CRB-65 score were determined on admission. Results: MR-proANP, CT-proAVP and PCT levels, but not CRP, increased with increasing severity of CAP, classified according to the CRB-65 score. In patients who died during 28-day follow-up, median MR-proANP and CT-proAVP levels (respectively 237.0 vs. 93.5 pmol/l and 44.2 vs. 12.4 pmol/l, each p < 0.0001) were significantly higher than in survivors. In receiver operating characteristic (ROC) analysis for survival, the area under the curve (AUC) values for CT-proAVP (0.86, 95% CI 0.83-0.89) and MR-proANP (0.76, 95% CI 0.72-0.80) were similar to the AUC of CRB-65 (0.73, 95% CI 0.70-0.77). In multivariable Cox proportional-hazards regression analyses including MR-proANP/CTproAVP, coexisting illnesses and CRB-65, increased MR-proANP and CT-proAVP concentrations were the strongest predictors of mortality. Conclusions: MR-proANP and CT-proAVP are useful new biomarkers for the risk stratification of CAP patients. They are significantly lower in CAP survivors and correlate with the severity of the disease measured by CRB-65 score.