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Preventable Proportion of Severe Infections Acquired in Intensive Care Units: Case-Mix Adjusted Estimations from Patient-Based Surveillance Data

Published online by Cambridge University Press:  10 May 2016

Marie-Laurence Lambert*
Healthcare Associated Infections Unit, Scientific Institute of Public Health, Brussels, Belgium
Geert Silversmit
Department of Applied Mathematics and Computer Science, Ghent University, Ghent, Belgium
Anne Savey
Centre de Coordination de la Lutte Contre les Infections Nosocomiales (CCLIN) Sud-Est, Healthcare Associated Infection Control Center/CNRS UMR5558 Lyon 1 University, Lyon, France
Mercedes Palomar
Universitat Autonoma de Barcelona, Barcelona, Spain Critical Care Department, Institut de Recerca Biomedica, Arnau de Vilanova University Hospital, Lleida, Spain
Michael Hiesmayr
Department of Anaesthesia, General Intensive Care and Pain Control, Medical University of Vienna, Vienna, Austria
Antonella Agodi
Department Gian Filippo Ingrassia, University of Catania, Catania, Italy
Bart Van Rompaye
Department of Applied Mathematics and Computer Science, Ghent University, Ghent, Belgium
Karl Mertens
Healthcare Associated Infections Unit, Scientific Institute of Public Health, Brussels, Belgium
Stijn Vansteelandt
Department of Applied Mathematics and Computer Science, Ghent University, Ghent, Belgium
Health-care Associated Infections Unit, Scientific Institute of Public Health, Rue Juliette Wytsmanstraat 14, 1050 Brussels, Belgium (



More than 10% of patients admitted to intensive care units (ICUs) experience a severe, healthcare-associated infection, such as ventilator-associated pneumonia (VAP) or bloodstream infection (BSI). What could be a public health target for prevention is hotly debated, because properly adjusting for intrinsic risk factors in the patient population is difficult. We aimed to estimate the proportion of ICU-acquired VAP and BSI cases that are amenable to prevention in routine conditions.


We analyzed routine data collected prospectively according to the European standard protocol for patient-based surveillance of healthcare-acquired infections in ICUs. We computed the number of infections to be expected if, after adjustment for case mix, the infection incidence in ICUs with higher infection rates could be reduced to that of the top-tenth-percentile-ranked ICU. Computations came from model-based simulation of individual patient profiles over time in the ICU. The preventable proportion was computed as the number of observed cases minus the number of expected cases divided by the number of observed cases.


Data for 78,222 patients admitted for more than 2 days to 525 ICUs in 6 European countries from 2005 to 2008 were available for analysis. We calculated that 52% of VAP and 69% of BSI was preventable.


Our pragmatic, if highly conservative, estimates quantify the potential for prevention of VAP and BSI in routine conditions, assuming that variation in infection incidence between ICUs can be eliminated with improved quality of care, apart from variation attributable to differential case mix.

Original Article
Copyright © The Society for Healthcare Epidemiology of America 2014

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