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.