Surveillance of nosocomial infection is the foundation of infection control. Nosocomial infection surveillance data ought to be summarized, reported, and fed back to health care personnel for corrective action. Using the Japanese Nosocomial Infection Surveillance (JANIS) data, we determined the incidence of nosocomial infections in intensive care units (ICUs) of Japanese hospitals and assessed the impact of nosocomial infections on mortality and length of stay. We also elucidated individual and environmental factors associated with nosocomial infections, examined the benchmarking of infection rates and developed a practical tool for comparing infection rates with case-mix adjustment. The studies carried out to date using the JANIS data have provided valuable information on the epidemiology of nosocomial infections in Japanese ICUs, and this information will contribute to the development of evidence-based infection control programs for Japanese ICUs. We conclude that current surveillance systems provide an inadequate feedback of nosocomial infection surveillance data and, based on our results, suggest a methodology for assessing nosocomial infection surveillance data that will allow infection control professionals to maintain their surveillance systems in good working order.

OBJECTIVESTo determine the incidence of sepsis in Japanese intensive care units (ICUs) and to evaluate the impact of sepsis on mortality and length of stay (LOS).

METHODSUsing the JANIS database for the period between June 2002 and June 2004, 21,895 eligible patients aged ≥16 years, hospitalized in 28 participating ICUs for ≥24 hours, were monitored until ICU discharge. Adjusted hazard ratio (HR) with 95% confidence interval (CI) for the incidence of sepsis was calculated using Cox's proportional hazard model. Standardized mortality ratio (SMR) was calculated on the basis of the crude mortality in patients without nosocomial infection (NI) for respective APACHE II categories. Mean LOS for survivors was assessed by two-way analysis of variance with adjustment for APACHE II.

RESULTSSepsis was diagnosed in 450 patients (2.1%), with 228 meeting the definition on ICU admission and 222 during the ICU stay. The overall incidence of sepsis was 1.02/100 admissions or 2.00/1000 patient-days. A significantly higher HR for the incidence of sepsis was found in men (1.54, 95% CI: 1.14-2.07), APACHE II ≥21 (2.92, 95% CI: 1.92-4.44), ventilator use (3.30, 95% CI: 1.98-5.49), and central venous catheter use (3.45, 95% CI: 1.90-6.28). SMR was determined to be 1.18 (95% CI: 0.82-1.21) in NI patients without sepsis and 2.43 (95% CI: 1.88-3.09) in NI patients with sepsis. Mean LOS for survivors was calculated to be 11.8 days (95% CI: 11.3-12.4) in NI patients without sepsis and 15.0 days (95% CI: 13.3-17.0) in NI patients with sepsis compared with 3.8 days (95% CI: 3.8-3.9) in patients without NI.

CONCLUSIONSSepsis is not very common in Japanese ICUs, but its development leads to further increases in mortality and LOS in patients with NI.

OBJECTIVETo examine whether nosocomial infection risk increases with APACHE II score, which is an index of severity-of-illness, in intensive care unit (ICU) patients.

METHODSUsing the Japanese Nosocomial Infection Surveillance database, 8,587 patients admitted to 34 participating ICUs between July 2000 and May 2002, aged 16 years or older, who had stayed in the ICU for 2 days or longer, had not transferred to another ICU, and had not been infected within 2 days after ICU admission, were followed until ICU discharge, Day 14 after ICU admission, or the development of nosocomial infection. Adjusted odds ratios with their 95% confidence intervals for nosocomial infections were calculated using logistic regression models, which incorporated sex, age, operation, ventilator; central venous catheter, and APACHE II score (0-5, 6-10, 11-15, 16-20, 21-25, 26-30, and 31+).

RESULTSThere were 683 patients with nosocomial infections. Adjusted odds ratios for nosocomial infections gradually increased with APACHE II score. Women and elective operation showed significantly low odds ratios, while urgent operation, ventilator, and central venous catheter showed significantly high odds ratios. Age had no significant effect on the development of nosocomial infection.

CONCLUSIONSNosocomial infection risk increases with APACHE II score. APACHE II score may be a good predictor of nosocomial infections in ICU patients.

OBJECTIVESTo 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.

METHODSBy 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.

RESULTSAfter 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).

CONCLUSIONSThe 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.