Dekkers Olaf M
Leids Universitair Medisch Centrum, afd. Klinische Epidemiologie, Endocrinologie en Metabole Ziekten, Leiden, The Netherlands.
Ned Tijdschr Geneeskd. 2009;153:A491.
Selective decontamination reduces the mortality rate in ICU patients by about 3%. This was the conclusion of a recently published trial by De Smet et al. Because of possible ecological changes in the ICU by selective decontamination, a cluster-randomized design was used. As a consequence of this cluster randomization, the study lacked concealed allocation. Treatment allocation may therefore have been determined by prognostic factors. The discrepancies in baseline characteristics between the treatment groups are likely to be due to non-concealed allocation. For this reason the analysis was performed after making statistical adjustments for these discrepancies. The conclusion that selective bacterial decontamination reduces mortality is based on this adjusted analysis. This assumes that all differences between treatment groups were measured. This assumption cannot be proven and the possibility remains that the reduction in mortality found in this study is not a proper reflection of treatment effect.
选择性去污可使重症监护病房（ICU）患者的死亡率降低约3%。这是德·斯梅特等人最近发表的一项试验得出的结论。由于选择性去污可能会使ICU出现生态变化，因此采用了整群随机设计。由于这种整群随机化，该研究缺乏分配隐藏。因此，治疗分配可能由预后因素决定。治疗组之间基线特征的差异很可能是由于缺乏分配隐藏所致。出于这个原因，在对这些差异进行统计调整后进行了分析。选择性细菌去污可降低死亡率这一结论是基于这种调整后的分析得出的。这假定测量了治疗组之间的所有差异。这一假设无法得到证实，而且该研究中发现的死亡率降低可能并非治疗效果的真实反映这一可能性仍然存在。
