Table 2.

Independent Factors Associated With Length of Stay

Variable	Hazard Ratio (95% CI)	P Value
Prior antibiotic exposure	1.473 (1.297-1.672)	0.002
Pulmonary source of infection	1.670 (1.496-1.865)	<0.001
APACHE II Score (1-point increments)	1.066 (1.057-1.076)	<0.001
Inappropriate antibiotic therapy	1.390 (1.239-1.559)	0.004
Hospital-onset infection	1.486 (1.234-1.790)	0.034
Pre-culture length of stay (1-day increments)	1.012 (0.008-1.016)	0.001

CI = confidence interval; APACHE = Acute Physiology and Chronic Health Evaluation

Other variables included in the analysis for which the Cox-proportional hazards model was adjusted included male gender, age (1-year increments), underlying liver disease, underlying renal disease, underlying malignancy, prior hospitalization (within 90 days), and Charlson co-morbidity score. Hazard ratios greater than 1 indicate the factor is associated with a greater probability of remaining hospitalized. Patients who died were censored at the time of death because they did not reach the endpoint of "discharged alive from hospital."