Predicting the risk of documented ventilator-associated pneumonia for benchmarking: construction and validation of a score.
OBJECTIVE
: To build and validate a ventilator-associated pneumonia risk score for benchmarking. The rate of ventilator-associated pneumonia varies widely with case-mix, a fact that has limited its use for measuring intensive care unit performance.


METHODS
: We studied 1856 patients in the OUTCOMEREA database treated at intensive care unit admission by endotracheal intubation followed by mechanical ventilation for >48 hrs; they were allocated randomly to a training data set (n = 1233) or a validation data set (n = 623). Multivariate logistic regression was used. Calibration of the final model was assessed in both data sets, using the Hosmer-Lemeshow chi-square test and receiver operating characteristic curves.


RESULTS
: Independent risk factors for ventilator-associated pneumonia were male gender (odds ratio = 1.97, 95% confidence interval = 1.32-2.95); SOFA at intensive care unit admission (<3 [reference value], 3-4 [2.57, 1.39-4.77], 5-8 [7.37, 4.24-12.81], >8 [5.81 (3.2-10.52)], no use within 48 hrs after intensive care unit admission of parenteral nutrition (2.29, 1.52-3.45), no broad-spectrum antimicrobials (2.11, 1.46-3.06); and mechanical ventilation duration (<5 days (); 5-7 days (17.55, 4.01-76.85); 7-15 days (53.01, 12.74-220.56); >15 days (225.6, 54.3-936.7). Tests in the training set showed good calibration and good discrimination (area under the curve-receiver operating characteristic curve = 0.881), and both criteria remained good in the validation set (area under the curve-receiver operating characteristic curve = 0.848) and good calibration (Hosmer-Lemeshow chi-square = 9.98, p = .5). Observed ventilator-associated pneumonia rates varied across intensive care units from 9.7 to 26.1 of 1000 mechanical ventilation days but the ratio of observed over theoretical ventilator-associated pneumonia rates was >1 in only two intensive care units.


CONCLUSIONS
: The ventilator-associated pneumonia rate may be useful for benchmarking provided the ratio of observed over theoretical rates is used. External validation of our prediction score is needed.
Zahar
Jean-Ralph
JR
Microbiology and Infection Control Unit (J-RZ), Necker Teaching Hospital, Paris France.
Nguile-Makao
Moliere
M
Français
Adrien
A
Schwebel
Carole
C
Garrouste-Orgeas
Maité
M
Goldgran-Toledano
Dany
D
Azoulay
Elie
E
Thuong
Marie
M
Jamali
Samir
S
Cohen
Yves
Y
de Lassence
Arnaud
A
Timsit
Jean-François
JF
D000368:Aged; D019985:Benchmarking; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology*; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors