Which Multicenter Randomized Controlled Trials in Critical Care Medicine Have Shown Reduced Mortality? A Systematic Review

Abstract

Objectives: To determine which multicenter randomized controlled trials in critically ill patients have shown that the study intervention was associated with a statistically significant reduction in mortality. Our analysis provides an update to a report published 10 years ago. Data Sources: MEDLINE database and PubMed interface from inception until April 30, 2019. Study Selection: All adult multicenter randomized controlled trials that evaluated the effects of any intervention or monitoring system in critically ill patients and reported mortality as a primary or secondary outcome were included. Data Extraction: Numbers of centers and patients, type of intervention, reported mortality outcome, and rate and level of significance were extracted into predefined tables. Included randomized controlled trials were classified as reporting reduced, increased, or no effect of the intervention on mortality. Methodologic quality of trials was evaluated using the updated Consolidated Standards of Reporting Trials statement. Data Synthesis: A total of 212 trials met the inclusion criteria: 27 (13%) reported a significant reduction in mortality, 16 (7%) an increase in mortality, and 170 (80%) no difference in mortality (one study was reported in 2 groups). Of the 27 trials reporting reduced mortality, six had assessed interventions likely to decrease ventilator-induced lung injury, including low tidal volume, prone position, and neuromuscular blockers, demonstrating the negative effects of mechanical ventilation strategies or improved process of care rather than positive effects of new therapies. Seven of the 27 trials reported beneficial effects of noninvasive ventilation. Results from some positive randomized controlled trials, for example, studies of recombinant activated protein C, talactoferrin, interleukin-1 receptor antagonist in sepsis, and muscle relaxants in severe acute respiratory distress syndrome were not replicated in subsequent randomized controlled trials. Other interventions, for example, gastric tonometry, have been abandoned. Conclusions: A systematic literature search provided no conclusive evidence of any pharmacologic intervention that has consistently reduced mortality in critically ill patients. Strategies associated with improved or noninvasive mechanical ventilation were associated with reduced mortality.

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