Impact of surveillance of hospital-acquired infections on the incidence of ventilator-associated pneumonia in intensive care units: a quasi-experimental study

Table 2 Incidence rate ratio of ventilator-associated pneumonia for trends and disruption in 2007 in ICU

Characteristics	Intervention group: Interrupted surveillance, unit A		Control group: Continuous surveillance, unit B
	Adjusted IRR of VAP (95% CI)^a	P	Adjusted IRR of VAP (95% CI)^a	P
Bivariate model
Trend, per quarter	0.98 (0.93 to 1.03)	0.45	1.01 (0.97 to 1.05)	0.69
Period
Before surveillance disruption^b	1.00 (Ref.)		1.00 (Ref.)
After surveillance disruption^c	2.17 (1.05 to 4.47)	0.036	1.37 (0.74 to 2.55)	0.31
Full model^d
Trend, per quarter	0.98 (0.92 to 1.04)	0.43	1.02 (0.97 to 1.06)	0.50
Period
Before surveillance disruption^b	1.00 (Ref.)		1.00 (Ref.)
After surveillance disruption^c	2.31 (1.03 to 5.17)	0.042	1.36 (0.72 to 2.56)	0.35

NOTE: CI, confidence interval; IRR, incidence rate ratio; VAP, ventilator-associated pneumonia. ^aAfter multivariate Poisson regression. ^b Period 1 (2004 to 2006). ^c Period 2 (2007 to 2010). ^d Adjusted for gender, age, patient origin, immunosuppression, diagnosis category, antibiotics and SAPSII at admission in the unit. The two other variables, trend (per quarter) and period (period 1 vs. period 2), were forced in the model.

ISSN: 1364-8535