TABLE 5.

Univariate and multivariate Cox regression analysis about factors associated with outcome at 30 days in MDR-AB infections^a

Variableb	Univariate			Multivariate
	HR	95% CI	P	HR	95% CI	P
Age	1.01	0.78–1.12	0.09	1.01	1.001–1.03	0.04c
Male sex	1.73	0.44–1.17	0.53
Cause of ICU admission
Respiratory failure	1.87	0.89–2.2	0.08
Trauma	1.1	0.78–1.22	0.71
Septic shock not caused by KPC-Kp or MDR-AB	1.24	0.98–1.65	0.65
Cardiac/hemorrhagic shock/postsurgery	0.87	0.76–1.31	0.42
Comorbidities
Chronic liver disease	0.84	0.76–1.22	1.0
Neoplasm	1.08	0.12–9.75	1.0
Diabetes	3.62	0.44–29.69	0.28
Heart failure	0.82	0.74–1.9	0.2
Coronary artery disease	3.66	0.94–14.1	0.07
Chronic renal disease	2.13	0.25–17.9	0.68
COPD	1.26	0.32–4.99	1.0
Previous hospitalization (90 days)	3.62	0.44–29.6	0.28
Previous ICU admission (90 days)	2.13	0.25–17.98	0.68
Previous surgery (30 days)	1.93	0.55–6.69	0.38
Previous antibiotic therapy (30 days)	1.89	0.58–6.16	0.38
Colonization at time of ICU admission	0.52	0.05–5.39	0.48
Source of infection
Primary bacteremia	3.35	0.4–27.5	0.45
CVC-related bacteremia	0.84	0.67–1.31	1.0
Pneumonia	0.57	0.14–2.25	0.53
SSTI	0.44	0.08–1.02	0.15
Intra-abdominal	0.7	0.07–6.79	0.57
Isolation of a colistin-resistant strain	0.87	0.81–1.02	1.0
Other infections during ICU stay	1.93	0.39–9.41	0.51
Steroid therapy during ICU stay	0.64	0.18–2.2	0.56
Length of hospitalization	1.13	0.68–1.36	0.71
Length of ICU stay	0.8	0.7–1.33	0.54
Length of antibiotic therapy	0.77	0.56–1.81	0.8
SAPS II at time of infection onset	1.09	0.87–1.49	0.6
SAPS II at time of septic shock onset	1.17	0.28–1.56	0.82	1.02	1.003–1.04	0.02d
No. of antibiotics used
Only 1 as definitive therapy	0.45	0.22–1.12	0.34
2 in combination as definitive therapy	1.73	0.44–6.75	0.53
3 in combination as definitive therapy	0.66	0.21–2.06	0.56
4 in combination as definitive therapy	0.36	0.08–1.61	0.17
5 in combination as definitive therapy	0.66	0.45–1.32	1.0
Colistin-containing regimen as definitive therapy	0.25	0.03–2.09	0.28
Tigecycline-containing regimen as definitive therapy	1.64	0.47–5.7	0.55
Gentamicin-containing regimen as definitive therapy	0.87	0.76–2.1	0.7
Rifampin-containing regimen as definitive therapy	0.29	0.09–1.01	0.07
Carbapenem-containing regimen as definitive therapy	0.84	0.24–2.96	1.0
Use of colistin aerosol inhalation therapy	0.53	0.12–2.27	0.41
≥2 in vitro active antibiotics used within 24 h	0.56	0.41–2.12	0.22
Definitive therapy with ≥2 antibiotics displaying in vitro activity	0.7	0.07–6.79	0.57
Time to initial definitive therapy	0.64	0.31–1.96	0.9

^aMDR-AB, multidrug-resistant Acinetobacter baumannii.

^bICU, intensive care unit; COPD, chronic obstructive pulmonary disease; CVC, central venous catheter; SSTI, skin and soft tissue infection; SAPS, simplified acute physiology score.

^cAge >60 years.

^dSAPS II >45 points.