Laboratory of Biometry and Evolutionary Biology, CNRS, UMR 5558, Claude Bernard University of Lyon, Lyon, France.
Infect Control Hosp Epidemiol. 2010 Apr;31(4):388-94. doi: 10.1086/650754.
The strength of the association between intensive care unit (ICU)-acquired nosocomial infections (NIs) and mortality might differ according to the methodological approach taken.
To assess the association between ICU-acquired NIs and mortality using the concept of population-attributable fraction (PAF) for patient deaths caused by ICU-acquired NIs in a large cohort of critically ill patients.
Eleven ICUs of a French university hospital.
We analyzed surveillance data on ICU-acquired NIs collected prospectively during the period from 1995 through 2003. The primary outcome was mortality from ICU-acquired NI stratified by site of infection. A matched-pair, case-control study was performed. Each patient who died before ICU discharge was defined as a case patient, and each patient who survived to ICU discharge was defined as a control patient. The PAF was calculated after adjustment for confounders by use of conditional logistic regression analysis.
Among 8,068 ICU patients, a total of 1,725 deceased patients were successfully matched with 1,725 control patients. The adjusted PAF due to ICU-acquired NI for patients who died before ICU discharge was 14.6% (95% confidence interval [CI], 14.4%-14.8%). Stratified by the type of infection, the PAF was 6.1% (95% CI, 5.7%-6.5%) for pulmonary infection, 3.2% (95% CI, 2.8%-3.5%) for central venous catheter infection, 1.7% (95% CI, 0.9%-2.5%) for bloodstream infection, and 0.0% (95% CI, -0.4% to 0.4%) for urinary tract infection.
ICU-acquired NI had an important effect on mortality. However, the statistical association between ICU-acquired NI and mortality tended to be less pronounced in findings based on the PAF than in study findings based on estimates of relative risk. Therefore, the choice of methods does matter when the burden of NI needs to be assessed.
重症监护病房（ICU）获得性医院感染（NI）与死亡率之间的关联强度可能因所采用的方法学方法而异。
使用 ICU 获得性 NI 导致的患者死亡率的人群归因分数（PAF）概念，评估 ICU 获得性 NI 与死亡率之间的关联，该研究纳入了大量危重病患者。
法国一家大学医院的 11 个 ICU。
我们分析了 1995 年至 2003 年期间前瞻性收集的 ICU 获得性 NI 监测数据。主要结局是 ICU 获得性 NI 所致死亡率，按感染部位分层。进行了匹配对病例对照研究。每个 ICU 出院前死亡的患者均被定义为病例患者，每个 ICU 出院存活的患者均被定义为对照患者。使用条件逻辑回归分析调整混杂因素后，计算 PAF。
在 8068 例 ICU 患者中，共有 1725 例死亡患者成功与 1725 例对照患者相匹配。ICU 出院前死亡患者的 ICU 获得性 NI 归因 PAF 为 14.6%（95%置信区间 [CI]，14.4%-14.8%）。按感染类型分层，肺部感染的 PAF 为 6.1%（95% CI，5.7%-6.5%），中心静脉导管感染为 3.2%（95% CI，2.8%-3.5%），血流感染为 1.7%（95% CI，0.9%-2.5%），尿路感染为 0.0%（95% CI，-0.4%至 0.4%）。
ICU 获得性 NI 对死亡率有重要影响。然而，基于 PAF 的研究结果与基于相对风险估计的研究结果相比，ICU 获得性 NI 与死亡率之间的统计学关联往往不那么明显。因此，当需要评估 NI 的负担时，方法的选择很重要。
