ObjectiveTo investigate the relationship between baseline risk of death and reduced mortality after selective decontamination of the digestive tract in intensive care unit patients.DesignAnalysis of data from a meta-analysis of 23 randomized, controlled trials.PatientsA total of 4,142 adult intensive care unit patients from the 23 trials.Measurements and Main ResultsMortality for patients receiving selective decontamination of the digestive tract treatment was analyzed as a function of baseline risk of death at study entry, using weighted least squares regression across all 23 trials. In testing whether the slope of the regression is different than 1.0, the observed t value is 3.32 (p less than .004), suggesting that the efficacy of selective decontamination of the digestive tract in reducing mortality is significantly better in populations at high mortality risk at study entry.ConclusionsMortality reduction from selective decontamination of the digestive tract appears related to the mortality risk of patients at the time of study entry. Future trials should consider using baseline risk assessment as part of trial design and outcome analysis.(Crit Care Med 1996; 24:753-755)