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Intensive Care Medicine

, Volume 36, Issue 5, pp 781–789 | Cite as

Attributable mortality of ventilator-associated pneumonia: respective impact of main characteristics at ICU admission and VAP onset using conditional logistic regression and multi-state models

  • Molière Nguile-Makao
  • Jean-Ralph Zahar
  • Adrien Français
  • Alexis Tabah
  • Maité Garrouste-Orgeas
  • Bernard Allaouchiche
  • Dany Goldgran-Toledano
  • Elie Azoulay
  • Christophe Adrie
  • Samir Jamali
  • Christophe Clec’h
  • Bertrand Souweine
  • Jean-Francois TimsitEmail author
Original

Abstract

Purpose

Methods for estimating the excess mortality attributable to ventilator-associated pneumonia (VAP) should handle VAP as a time-dependent covariate, since the probability of experiencing VAP increases with the time on mechanical ventilation. VAP-attributable mortality (VAP-AM) varies with definitions, case-mix, causative microorganisms, and treatment adequacy. Our objectives here were to compare VAP-AM estimates obtained using a traditional cohort analysis, a multistate progressive disability model, and a matched-cohort analysis; and to compare VAP-AM estimates according to VAP characteristics.

Methods

We used data from 2,873 mechanically ventilated patients in the Outcomerea® database. Among these patients from 12 intensive care units, 434 (15.1%) experienced VAP; of the remaining patients, 1,969 (68.5%) were discharged alive and 470 (16.4%) died. With the multistate model, VAP-AM was 8.1% (95% confidence interval [95%CI], 3.1–13.1%) for 120 days’ complete observation, compared to 10.4% (5.6–24.5%) using a matched-cohort approach (2,769 patients) with matching on mechanical ventilation duration followed by conditional logistic regression. VAP-AM was higher in surgical patients and patients with intermediate (but not high) Simplified Acute Physiologic Score II values at ICU admission. VAP-AM was significantly influenced by time to VAP but not by resistance of causative microorganisms. Higher Logistic Organ Dysfunction score at VAP onset dramatically increased VAP-AM (to 31.9% in patients with scores above 7).

Conclusion

A multistate model that appropriately handled VAP as a time-dependent event produced lower VAP-AM values than conditional logistic regression. VAP-AM varied widely with case-mix. Disease severity at VAP onset markedly influenced VAP-AM; this may contribute to the variability of previous estimates.

Keywords

Nosocomial pneumonia Logistic regression Multistate models Benchmarking Critically ill 

Notes

Acknowledgments

OUTCOMEREA is a non-profit organization supported by nonexclusive educational grants from four pharmaceutical companies (Aventis Pharma, France; Wyeth; Pfizer, and MSD) and by research grants from three publicly funded French agencies (Centre National de la Recherche Scientifique [CNRS], Institut National pour la Santé et la Recherche Médicale [INSERM], and the French Ministry of Health).

Supplementary material

134_2010_1824_MOESM1_ESM.doc (46 kb)
Supplementary material 1 (DOC 46 kb)

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Copyright information

© Copyright jointly held by Springer and ESICM 2010

Authors and Affiliations

  • Molière Nguile-Makao
    • 1
  • Jean-Ralph Zahar
    • 1
    • 2
  • Adrien Français
    • 1
  • Alexis Tabah
    • 1
    • 3
  • Maité Garrouste-Orgeas
    • 1
    • 4
  • Bernard Allaouchiche
    • 5
  • Dany Goldgran-Toledano
    • 6
  • Elie Azoulay
    • 1
    • 7
  • Christophe Adrie
    • 8
  • Samir Jamali
    • 9
  • Christophe Clec’h
    • 1
    • 10
  • Bertrand Souweine
    • 11
  • Jean-Francois Timsit
    • 1
    • 3
    Email author
  1. 1.INSERM U823University Grenoble 1, Albert Bonniot InstituteGrenobleFrance
  2. 2.Microbiology and Infection Control UnitNecker Teaching HospitalParisFrance
  3. 3.Medical ICUAlbert Michallon Teaching HospitalGrenoble Cedex 9France
  4. 4.Medical-Surgical ICUSaint Joseph HospitalParisFrance
  5. 5.Surgical ICUEdouart Heriot HospitalLyonFrance
  6. 6.Medical-Surgical ICUGonesse HospitalGonesseFrance
  7. 7.Medical ICUSaint Louis Teaching HospitalParisFrance
  8. 8.Medical-Surgical ICUDelafontaine HospitalSaint-DenisFrance
  9. 9.Medical-Surgical ICUDourdan HospitalDourdanFrance
  10. 10.Medical-Surgical ICUAvicenne Teaching HospitalBobignyFrance
  11. 11.Medical ICUGabriel Montpied University HospitalClermont-FerrandFrance

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