Impact of Intensive Care Unit-Acquired Infection on Hospital Mortality in Japan: A Multicenter Cohort Study

ABSTRACT

Objectives: To elucidate factors associated with hospital mortality in intensive care unit (ICU) patients and to evaluate the impact of ICU-acquired infection on hospital mortality in the context of the drug resistance of pathogens. Methods: By using the Japanese Nosocomial Infection Surveillance (JANIS) database, 7,374 patients who were admitted to the 34 participating ICUs between July 2000 and May 2002, were aged 16 years or older, and who stayed in the ICU for 48 to 1,000 hours, did not transfer to another ICU, and did not become infected within 2 days after ICU admission, were followed up until hospital discharge or to Day 180 after ICU discharge. Adjusted hazard ratios (HRs) with the 95% confidence intervals (CIs) for hospital mortality were calculated using Cox’s proportional hazard model. Results: After adjusting for sex, age, and severity-of-illness (APACHE II score), a significantly higher HR for hospital mortality was found in ventilator use, central venous catheter use, and ICU-acquired drug-resistant infection, with a significantly lower HR in elective or urgent operations and urinary catheter use. The impact of ICU-acquired infection on hospital mortality was different between drug-susceptible pathogens (HR 1.11, 95% CI 0.94-1.31) and drug-resistant pathogens (HR 1.42, 95% CI 1.15-1.77). Conclusions: The use of a ventilator or a central venous catheter, and ICU-acquired drug-resistant infection were associated with a high risk of hospital mortality in ICU patients. The potential impact on hospital mortality emphasizes the importance of preventive measures against ICU-acquired infections, especially those caused by drug-resistant pathogens.