Structural equation modeling the “control of gut overgrowth” in the prevention of ICU-acquired Gram-negative infection

Table 1 Characteristics of studies

	Observational studies	Infection prevention studies
	No intervention	Non-decontamination	Anti-septic	TAP ± PPAP/EAP
Study characteristics
Sources	Table S1	Table S2	Table S3	Table S4
Number of studies^a	111	45	13	48
Origin from systematic review^b	46	38	7	38
North American ICUs^c	32	10	6	3
LOS > 7 days	88	37	9	37
MV for > 48 h for < 90%^d	21	1	5	11
Trauma ICUs^e	22	8	2	14
PPAP use in the control group^f	0	0	1	8
Study publication year (range)	1987–2014	1987–2017	2000–2018	1984–2018
Group characteristics
Numbers of patients per control group (median; IQR)^g	279 135–707	75 61–161	96 36–217	86 31–128
Prevention effect size (odds ratio; 95% CI; number of studies)
VAP	NA	0.73; 0.66–0.80 (45) (see Fig S2)	0.89; 0.72–1.11 (10) (see Fig S3)	0.38; 0.33–0.44 (37)^h (see Fig S4)
Bacteremia	NA	0.99; 0.71–1.39 (6) (see Fig S5)	0.72; 0.66–0.79 (10) (see Fig S6)	0.69; 0.62–0.76 (33)ⁱ (see Fig S7)

^aSeveral studies had more than one control and/or intervention group. Hence, the number of groups does not equal the number of studies
^bStudies that were sourced from 16 systematic reviews (references in web-only supplementary)
^cStudy originating from an ICU in Canada of the USA
^dStudies for which less than 90% of patients were reported to receive > 48 h of MV
^eTrauma ICU arbitrarily defined as an ICU with more than 50% of admissions for trauma
^fUse of PPAP for control group patients. PPAP is protocolized parenteral antibiotic prophylaxis
^gData is median and inter-quartile range (IQR)
^hVAP prevention effect size for studies not including versus including PPAP in the antibiotic intervention was 0.44; 0.36–0.55 (n = 13) and 0.34; 0.28–0.41 (n = 24), respectively (see Fig S4)
ⁱBacteremia prevention effect size for studies not including versus including PPAP in the antibiotic intervention was 0.77; 0.68–0.88 (n = 10) and 0.57; 0.48–0.67 (n = 22), respectively (see Fig S7)

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