Validation of a Clinical Prediction Model for Early Admission to the Intensive Care Unit of Patients With Pneumonia

Authors

  • José Labarère MD,

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    • Drs. Labarère and Schuetz contributed equally to this paper.

  • Philipp Schuetz MD,

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    • Drs. Labarère and Schuetz contributed equally to this paper.

  • Bertrand Renaud MD,

    1. From the Quality of Care Unit, Grenoble University Hospital (JL), Grenoble, France; TIMC, UMR 5525 CNRS Université Joseph Fourier-Grenoble 1 (JL), Grenoble, France; the Harvard School of Public Health (PS), Boston, MA; the Service d’urgence, Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Henri Mondor-Albert Chenevier (BR), Créteil, France; the Laboratoire d’Investigation Clinique (EA 4393), Université Paris Est Créteil, Faculté de Médecine (BR), Créteil, France; the Department of Emergency Medicine. Hôpital Cochin, Assistance Publique–Hôpitaux de Paris (YEC), Paris, France; the Université Paris Descartes (YEC), Paris, France; and the Medical University Clinic, Kantonsspital Aarau (WA, BM), Switzerland.
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  • Yann-Erick Claessens MD,

    1. From the Quality of Care Unit, Grenoble University Hospital (JL), Grenoble, France; TIMC, UMR 5525 CNRS Université Joseph Fourier-Grenoble 1 (JL), Grenoble, France; the Harvard School of Public Health (PS), Boston, MA; the Service d’urgence, Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Henri Mondor-Albert Chenevier (BR), Créteil, France; the Laboratoire d’Investigation Clinique (EA 4393), Université Paris Est Créteil, Faculté de Médecine (BR), Créteil, France; the Department of Emergency Medicine. Hôpital Cochin, Assistance Publique–Hôpitaux de Paris (YEC), Paris, France; the Université Paris Descartes (YEC), Paris, France; and the Medical University Clinic, Kantonsspital Aarau (WA, BM), Switzerland.
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  • Werner Albrich MD,

    1. From the Quality of Care Unit, Grenoble University Hospital (JL), Grenoble, France; TIMC, UMR 5525 CNRS Université Joseph Fourier-Grenoble 1 (JL), Grenoble, France; the Harvard School of Public Health (PS), Boston, MA; the Service d’urgence, Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Henri Mondor-Albert Chenevier (BR), Créteil, France; the Laboratoire d’Investigation Clinique (EA 4393), Université Paris Est Créteil, Faculté de Médecine (BR), Créteil, France; the Department of Emergency Medicine. Hôpital Cochin, Assistance Publique–Hôpitaux de Paris (YEC), Paris, France; the Université Paris Descartes (YEC), Paris, France; and the Medical University Clinic, Kantonsspital Aarau (WA, BM), Switzerland.
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  • Beat Mueller MD

    1. From the Quality of Care Unit, Grenoble University Hospital (JL), Grenoble, France; TIMC, UMR 5525 CNRS Université Joseph Fourier-Grenoble 1 (JL), Grenoble, France; the Harvard School of Public Health (PS), Boston, MA; the Service d’urgence, Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Henri Mondor-Albert Chenevier (BR), Créteil, France; the Laboratoire d’Investigation Clinique (EA 4393), Université Paris Est Créteil, Faculté de Médecine (BR), Créteil, France; the Department of Emergency Medicine. Hôpital Cochin, Assistance Publique–Hôpitaux de Paris (YEC), Paris, France; the Université Paris Descartes (YEC), Paris, France; and the Medical University Clinic, Kantonsspital Aarau (WA, BM), Switzerland.
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  • Drs. Albrich and Schuetz have consulted for BRAHMS, BioMerieux Clinical Diagnostics (Marcy-l’Étoile, France); Dr. Claessens has grants pending with Thermo Fisher Scientific (Waltham, MA), and Roche Diagnostics (Basel, Switzerland), has lectured for Amgen (Thousand Oaks, CA) and Roche Diagnostics, and is on the board for Laboratoire Francais du Fractionnement et des Biotechnologies (Essonne, France).

  • Supervising Editor: Brian J. O’Neil, MD.

Address for correspondence and reprints: Dr. José Labarère; e-mail: jlabarere@chu-grenoble.fr, jose.labarere@laposte.net.

Abstract

ACADEMIC EMERGENCY MEDICINE 2012; 19:993–1003 © 2012 by the Society for Academic Emergency Medicine

Abstract

Objectives:  The Risk of Early Admission to the Intensive Care Unit (REA-ICU) index is a clinical prediction model that was derived based on 4,593 patients with community-acquired pneumonia (CAP) for predicting early admission to the intensive care unit (ICU; i.e., within 3 days following emergency department [ED] presentation). This study aimed to validate the REA-ICU index in an independent sample.

Methods:  The authors retrospectively stratified 850 CAP patients enrolled in a multicenter prospective randomized trial conducted in Switzerland, using the REA-ICU index, alternate clinical prediction models of severe pneumonia (SMART-COP, CURXO-80, and the 2007 IDSA/ATS minor severity criteria), and pneumonia severity assessment tools (the Pneumonia Severity Index [PSI] and CURB-65).

Results:  The rate of early ICU admission did not differ between the validation and derivation samples within each risk class of the REA-ICU index, ranging from 1.1% to 1.8% in risk class I to 27.1% to 27.6% in risk class IV. The areas under the receiver operating characteristic (ROC) curve were 0.76 (95% confidence interval [CI] = 0.70 to 0.83) and 0.80 (95% CI = 0.77 to 0.83) in the validation and derivation samples, respectively. In the validation sample, the REA-ICU index performed better than the pneumonia severity assessment tools, but failed to demonstrate an accuracy advantage over alternate prediction models in predicting ICU admission.

Conclusions:  The REA-ICU index reliably stratifies CAP patients into four categories of increased risk for early ICU admission within 3 days following ED presentation. Further research is warranted to determine whether inflammatory biomarkers may improve the performance of this clinical prediction model.

Abstract

Resumen

Objetivos:  El índice Riesgo de Ingreso Precoz en la Unidad de Cuidados Intensivos (Risk of Early Admission to the Intensive Care Unit, -REA-ICU-) es un modelo de predicción clínica obtenido a partir de 4.593 pacientes con neumonía adquirida en la comunidad (NAC) para predecir el ingreso precoz en la unidad de cuidados intensivos (UCI) durante los 3 días siguientes a la atención en el servicio de urgencias [SU]). El objetivo de este estudio fue validar el índice REA-ICU en una muestra independiente.

Método:  Ochocientos cincuenta pacientes con NAC incluidos en un estudio prospectivo aleatorizado multicéntrico llevado a cabo en Suiza fueron clasificados retrospectivamente mediante el índice de REA-ICU, mediante los modelos de predicción clínica alternativos de neumonía grave (SMART-COP, CURXO-80 y los criterios de gravedad menor IDSA/ATS 2007) y mediante las escalas de valoración de la gravedad de la neumonía (Pneumonia Severity Index y CURB-65).

Resultados:  El porcentaje de ingreso precoz en UCI no difirió entre las muestras de derivación y de validación del modelo en cada una de las clases de riesgo del índice REA-ICU, cuyo rango fue de 1,1% y 1,8% en la clase de riesgo I, y de 27,1% y 27,6% en la clase de riesgo IV. Las áreas bajo la curva ROC fueron 0,76 (intervalo de confianza del 95% [IC 95%] = 0,70 a 0,83) y 0,80 (IC 95% = 0,77 a 0,83) en las muestras de derivación y de validación, respectivamente. En la muestra de validación, el índice REA-ICU mostró un mejor rendimiento que las escalas de valoración de la gravedad de la neumonía, pero no fue superior a los modelos de predicción alternativos para predecir el ingreso en UCI.

Conclusiones:  El índice REA-ICU clasifica de forma fidedigna a los pacientes con NAC en cuatro categorías de riesgo de ingreso precoz en la UCI durante los tres días siguientes a la atención en el SU. En el futuro será necesario llevar a cabo estudios que determinen si los biomarcadores inflamatorios pueden mejorar el rendimiento de este modelo de predicción clínica.

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