Red blood cell distribution width [RDW] and long-term mortality after community-acquired pneumonia. A comparison with proadrenomedullin

Abstract

Proadrenomedullin (proADM), a cardiovascular biomarker, has shown high prognostic power for community-acquired pneumonia (CAP) outcomes. Red-blood-cell distribution width (RDW), linked to cardiovascular disorders, has been associated with short-term and medium-term mortality after CAP. Our objective was to assess the accuracy of both biomarkers for CAP long-term mortality (>90 days).Adults hospitalized with CAP underwent blood proADM, RDW, C-reactive protein (CRP) and procalcitonin (PCT) measurements at admission, and were evaluated after 30, 90, and 180 days, and 1, 2, and 3 years, until either death or 5 years of follow-up.A group of 265 patients were recruited, with an average follow-up 1018 ± 539 days. Of these, 217 were followed for 1 year, and 187 for 3 years. Levels of both proADM and RDW were higher in those who died in the short term (p = 0.017 and p < 0.0001, respectively), medium term (p = 0.004 and p < 0.0001, respectively) and long term (p < 0.0001 and p < 0.0001, respectively). RDW showed lower accuracy (30-day AUC, 0.673) than proADM (AUC, 0.816), PSI (AUC, 0.846), and CURB65 (AUC, 0.817) scores for short-term and medium-term mortality prediction. However, accuracy was similar (3-year AUC, 0.692, 0.698, 0.743, and 0.704, respectively) for long-term mortality, and RDW > 14% (RDW > 14) increased the prediction power of both PSI (AUC, 0.743 vs 0.779; p < 0.0001) and CURB65 (AUC, 0.704 vs 0.747; p < 0.0001) scores, as did proADM. RDW > 14 + PSI and RDW > 14 + CURB65 associations had a sensitivity for long-term mortality of 80.8%–90% and 74%–90%, and a specificity of 56.7%–61.5% and 59.3%–64.2%, respectively. Both proADM and RDW > 14 (HR, 4.116) were independent risk factors for long-term mortality and were associated with poorer survival.Our findings agree with the suggested association between cardiovascular disease and long-term CAP mortality. RDW, routinely provided as part of the whole blood count, and especially associated with clinical scores, can provide useful information about long-term CAP outcomes.