Risk Factors of Multidrug-Resistant Bacteria in Lower Respiratory Tract Infections: A Systematic Review and Meta-Analysis

Table 4

Subgroup analysis of studies reporting prior antibiotic treatment as a risk factor.

Subgroups	No. of included studies	Heterogeneity	Synthesized results
Divided by diagnosis
CAP [14, 16, 28]	3	I^2 = 67.1%,	OR: 1.92; 95% CI: 0.65 to 5.70
HAP [26, 37, 38]	3	I^2 = 11.8%,	OR: 2.40; 95% CI: 1.52 to 3.80
VAP [34, 41]	2	I^2 = 0.0%,	OR: 2.63; 95% CI: 1.24 to 5.55
Pneumonia [15, 36]	2	I^2 = 0.0%,	OR: 3.87; 95% CI: 1.97 to 7.59
Bronchiectasis [30]	1	NA	OR: 4.28; 95% CI: 1.43 to 12.80
AECOPD [42]	1	NA	OR: 2.40; 95% CI: 1.21 to 4.75
Divided by kinds of organisms
GNB [14, 16, 30, 36]	4	I^2 = 72.7%,	OR: 2.65; 95% CI: 1.01 to 6.92
GNB and GPB [16, 26, 28, 34, 38, 41, 42]	7	I^2 = 0.0%,	OR: 2.44; 95% CI: 1.81 to 3.30
GPB [37]	1	NA	OR: 3.81; 95% CI: 1.01 to 14.39
Divided by definitions of MDR
Definition A [14, 16, 26, 30, 34, 36–38, 41]	9	I^2 = 40.4%,	OR: 2.57; 95% CI: 1.72 to 3.82
Definition B [15, 42]	2	I^2 = 0.0%,	OR: 2.56; 95% CI: 1.47 to 4.45
No definition [28]	1	NA	OR: 3.54; 95% CI: 0.98 to 12.77

Using random-effects model; NA: not applicable; CAP: community-acquired pneumonia; HAP: hospital-acquired pneumonia; AECOPD: acute exacerbation of chronic obstructive pulmonary disease; GNB: Gram-negative bacteria; GPB: Gram-positive bacteria; GNB and GPB: Gram-negative bacteria and Gram-positive bacteria; MDROs: multidrug-resistant organisms; Definition A: MDROs defined as resistance to ≥3 antimicrobial classes known to be active against these pathogens; Definition B: MDROs defined as methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing and carbapenem-resistant Klebsiella pneumoniae and Escherichia coli, AB, and Stenotrophomonas maltophilia; No definition: no elaboration on the definition of MDROs.