Objectives: To determine how many multicenter, randomized controlled trials have been published that assess mortality as a primary outcome in the adult intensive care unit population, and to evaluate their methodologic quality.
Data source: A sensitive search strategy for randomized controlled trials was conducted in the Cochrane Central Register of Controlled Trials and in MedLine using the PubMed interface.
Study selection: All publications of adult, multicenter randomized controlled trials carried out in the intensive care unit, with mortality as a primary outcome, and including >50 patients were selected.
Data extraction: Seventy-two randomized controlled trials were retrieved and were classified according to their effect on mortality: beneficial, detrimental, or neutral.
Data synthesis: Ten of the studies reported a positive impact of the studied intervention on mortality, seven studies reported a detrimental effect of the intervention, and 55 studies showed no effect on mortality.
Conclusions: This literature search demonstrates that relatively few of the randomized controlled trials conducted in intensive care units and using mortality as a primary outcome show a beneficial impact of the intervention on the survival of critically ill patients. Methodological limitations of some of the randomized controlled trials may have prevented positive results. Other forms of evidence and end points other than mortality need to be considered when evaluating interventions in critically ill patients.