Open Access Highly Accessed Research article

Enhancement of CURB65 score with proadrenomedullin (CURB65-A) for outcome prediction in lower respiratory tract infections: Derivation of a clinical algorithm

Werner C Albrich1, Frank Dusemund1, Kristina Rüegger1, Mirjam Christ-Crain2, Werner Zimmerli3, Thomas Bregenzer4, Sarosh Irani5, Ulrich Buergi6, Barbara Reutlinger7, Beat Mueller1* and Philipp Schuetz8

Author Affiliations

1 Medical University Department of the University of Basel, Kantonsspital Aarau, Switzerland

2 Department of Internal Medicine, Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Basel, Switzerland

3 Basel University Medical Clinic, Department of Internal Medicine, Kantonsspital Liestal, Switzerland

4 Department of Infectious Diseases, Kantonsspital Aarau, Switzerland

5 Department of Pulmonary Medicine, Kantonsspital Aarau, Switzerland

6 Department of Emergency Medicine, Kantonsspital Aarau, Switzerland

7 Department of Nursing, Kantonsspital Aarau, Switzerland

8 Harvard School of Public Health, Boston (MA), USA

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BMC Infectious Diseases 2011, 11:112  doi:10.1186/1471-2334-11-112

Published: 3 May 2011



Proadrenomedullin (ProADM) confers additional prognostic information to established clinical risk scores in lower respiratory tract infections (LRTI). We aimed to derive a practical algorithm combining the CURB65 score with ProADM-levels in patients with community-acquired pneumonia (CAP) and non-CAP-LRTI.


We used data of 1359 patients with LRTI enrolled in a multicenter study. We chose two ProADM cut-off values by assessing the association between ProADM levels and the risk of adverse events and mortality. A composite score (CURB65-A) was created combining CURB65 classes with ProADM cut-offs to further risk-stratify patients.


CURB65 and ProADM predicted both adverse events and mortality similarly well in CAP and non-CAP-LRTI. The combined CURB65-A risk score provided better prediction of death and adverse events than the CURB65 score in the entire cohort and in CAP and non-CAP-LRTI patients. Within each CURB65 class, higher ProADM-levels were associated with an increased risk of adverse events and mortality. Overall, risk of adverse events (3.9%) and mortality (0.65%) was low for patients with CURB65 score 0-1 and ProADM ≤0.75 nmol/l (CURB65-A risk class I); intermediate (8.6% and 2.6%, respectively) for patients with CURB65 score of 2 and ProADM ≤1.5 nmol/l or CURB classes 0-1 and ProADM levels between 0.75-1.5 nmol/L (CURB65-A risk class II), and high (21.6% and 9.8%, respectively) for all other patients (CURB65-A risk class III). If outpatient treatment was recommended for CURB65-A risk class I and short hospitalization for CURB65-A risk class II, 17.9% and 40.8% of 1217 hospitalized patients could have received ambulatory treatment or a short hospitalization, respectively.


The new CURB65-A risk score combining CURB65 risk classes with ProADM cut-off values accurately predicts adverse events and mortality in patients with CAP and non-CAP-LRTI. Additional prospective cohort or intervention studies need to validate this score and demonstrate its safety and efficacy for the management of patients with LRTI.

Trial Registration

Procalcitonin-guided antibiotic therapy and hospitalisation in patients with lower respiratory tract infections: the prohosp study; Identifier: ISRCTN: ISRCTN95122877