Incidence, temporal trend and factors associated with ventilator-associated pneumonia in mainland China: a systematic review and meta-analysis

Table 1 The results of subgroup analyses by methodological quality and pre-defined setting characteristics

Subgroups		Studies	Sample size	Estimate (%)^a	95% CI (%)	I ² (%)	p value^b
Overall^c		93	71,816	23.8	20.6–27.2	98.9	-
Clinical department	General ICU	11	5388	18.3	11.3–26.6	97.7	0.310
	Neonatal ward	4	136	26.1	9.4–47.6	85.5
	Neonatal ICU	7	3938	15.7	3.2–35.0	99.4
	Pediatric ICU	6	721	30.2	18.7–43.2	91.8
	Respiratory ICU	5	607	27.4	23.3–31.7	15.2
	Surgical ICU	1	85	29.4	20.3–39.5	-
Diagnostic criteria^d	By Chinese Critical Care Medicine Society in 2013 ²⁶	3	174	38.4	31.4–45.8	0.0	<0.001
	By the Chinese Ministry of Health in 2001 ²⁵	29	46,894	20.0	15.1–25.3	99.1
	By Chinese Thoracic Society in 1999 ²⁷	35	13,979	27.2	22.2–32.5	97.6
Hospital level	Tertiary	75	58,704	23.6	19.7–27.6	99.0	0.574
	Non-tertiary	16	2703	26.4	17.7–36.2	96.3
Risk of bias	High	9	1286	26.3	17.1–36.6	88.2	0.687
	Moderate	43	17,973	24.6	20.8–28.5	96.8
	Low	41	52,557	22.2	17.4–27.4	99.2

CI confidence interval, ICU intensive care unit, VAP ventilator-associated pneumonia
^aPooled estimates were calculated by a random-effects model
^bThe Q test for heterogeneity was used to compare the incidence across subgroups
^cStudies that reported the cumulative incidence of VAP
^dA summary of diagnostic requirements for the three published sets of criteria is presented in Additional file 1: Table S5

ISSN: 1471-2334