• Martina Baiardo Redaelli, Giovanni Landoni, Stefania Di Sanzo, Samuele Frassoni, Chiara Sartini, Luca Cabrini, Giacomo Monti, Mara Scandroglio, Alberto Zangrillo, and Rinaldo Bellomo.
• Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milan, Italy. Electronic address: baiardoredaelli.martina@hsr.it.
• J Crit Care. 2017 Oct 1; 41: 107-111.

PurposeConfounders in randomized controlled trials (RCTs) reporting significant effects on mortality in critically ill patients using non-surgical techniques have not been systematically explored. We aimed to identify factors unrelated to the reported intervention that might have affected the findings and robustness of such trials.MethodsWe searched Pubmed/MEDLINE for all RCTs on any non-surgical interventions reporting an effect on unadjusted mortality in critically ill patients between 1/1/2000 and 1/12/2015. We assessed: the number needed to treat/harm (NNT or NNH), sample size, trial design (blinded/unblinded, single or multinational, single or multicenter (sRCT or mRCT)), intention to treat (ITT) analysis, and countries of origin.ResultsAlmost half of RCTs were sRCTs. Median sample size was small, and 1/3 were not analyzed according to ITT principle. Lack of ITT analysis was associated with greater effect size (p=0.0028). Harm was more likely in mRCTs (p=0.002) and/or in blinded RCTs (p=0.003). Blinded RCTs had double sample size (p=0.007) and an increased NNT/NNH (p=0.002). Finally, mRCTs had higher NNT (p=0.005) and NNH (p=0.02), and harm was only detected in studies from Western countries (p=0.007).ConclusionsThese observations imply that major systematic biases exist and affect trial findings irrespective of the intervention being studied.Copyright © 2017 Elsevier Inc. All rights reserved.

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