Internal Medicine, Grampians Health Ballarat, Ballarat, Victoria, Australia
Melbourne Medical School, The University of Melbourne, Melbourne, Victoria, Australia.
BMJ Open. 2024 Nov 20;14(11):e092030. doi: 10.1136/bmjopen-2024-092030.
To estimate the herd effects of anti-microbial-based decontamination (ABD) interventions on bloodstream infections (BSIs) among groups of intensive care unit (ICU) patients in relation to group mean length of stay (LOS). To deduce which of three competing hypotheses of ABD effect mediation best accounts for the observed effects.
Arms-based meta-regression of ICU-acquired BSI incidence against group mean LOS for control and interventions arms of ABD and non-ABD controlled trials each versus that in arms of observational studies.
Within controlled trials of ABD, intervention, concurrent control (CC) and non-concurrent (NCC) groups are directly, indirectly and non-exposed, respectively.
BSI incidence, both overall and for BSI subtypes.
In the arms-based meta-regression, the predicted BSI incidence per 100 patients in the ABD intervention arms increased from 4.6 (95% CI 3.8 to 5.5) at mean LOS 7 days to 13.0 (10.4-16.0) at mean LOS 20 days (n=60 arms) and CC arms 8.5 (6.7-11.0) increasing to 19.3 (14.8-24.8; n=52). These increases were double those in the observational (7.2; 6.1-8.5 increasing to 12.9; 10.4-16.7; n=99) and NCC arms and non-ABD arms. These results triangulate with the notional effect size observed in contrast-based meta-analyses.
The increased tempo of BSI acquisition, both overall and for various BSI subtypes, within intervention and CC groups of ABD randomised concurrent controlled trials versus other groups implicate rebound and spillover, respectively. Mechanisms other than colonisation resistance mediate ABD effects.
根据重症监护病房（ICU）患者群体的平均住院时间（LOS），估计基于抗菌的消毒（ABD）干预对血流感染（BSI）的群体效应。推断 ABD 效应中介的三个竞争性假设中，哪一个最能解释观察到的效果。
基于 ICU 获得性 BSI 发生率的手臂间荟萃回归，针对 ABD 和非 ABD 对照试验的对照和干预手臂与观察性研究手臂的组均 LOS 进行对比。
在 ABD 的对照试验中，干预、同期对照（CC）和非同期（NCC）组分别为直接、间接和非暴露组。
BSI 发生率，包括总体发生率和 BSI 亚型发生率。
在基于手臂的荟萃回归中，ABD 干预组每 100 例患者的预测 BSI 发生率从平均 LOS7 天时的 4.6（95%CI 3.8-5.5）增加到平均 LOS20 天时的 13.0（10.4-16.0）（n=60 组），CC 组从 8.5（6.7-11.0）增加到 19.3（14.8-24.8；n=52）。这些增加是观察性（7.2；6.1-8.5 增加到 12.9；10.4-16.7；n=99）和 NCC 组和非 ABD 组的两倍。这些结果与对比荟萃分析中观察到的理论效应大小相吻合。
ABD 随机同期对照试验的干预和 CC 组中，BSI 的总体获得率和各种 BSI 亚型的获得率都有所增加，这分别暗示了反弹和溢出效应。定植抵抗力以外的机制介导了 ABD 的效应。
