The increased risks of death and extra lengths of hospital and ICU stay from hospital-acquired bloodstream infections: a case–control study

OBJECTIVES Hospital-acquired bloodstream infections are known to increase the risk of death and prolong hospital stay, but precise estimates of these two important outcomes from well-designed studies are rare, particularly for non-intensive care unit (ICU) patients. We aimed to calculate accurate estimates, which are vital for estimating the economic costs of hospital-acquired bloodstream infections. DESIGN Case-control study. SETTING 9 Australian public hospitals. PARTICIPANTS All the patients were admitted between 2005 and 2010. PRIMARY AND SECONDARY OUTCOME MEASURES Risk of death and extra length of hospital stay associated with nosocomial infection. RESULTS The greatest increase in the risk of death was for a bloodstream infection with methicillin-resistant Staphylococcus aureus (HR=4.6, 95% CI 2.7 to 7.6). This infection also had the longest extra length of stay to discharge in a standard bed (12.8 days, 95% CI 6.2 to 26.1 days). All the eight bloodstream infections increased the length of stay in the ICU, with longer stays for the patients who eventually died (mean increase 0.7-6.0 days) compared with those who were discharged (mean increase: 0.4-3.1 days). The three most common organisms associated with Gram-negative infection were Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia. CONCLUSIONS Bloodstream infections are associated with an increased risk of death and longer hospital stay. Avoiding infections could save lives and free up valuable bed days.