Are blood transfusions associated with greater mortality rates?

Background: Studies have suggested worse outcomes in transfused patients and improved outcomes in patients managed with restricted blood transfusion strategies. The authors investigated the relation of blood transfusion to mortality in European intensive care units (ICUs). Methods: The Sepsis Occurrence in Acutely Ill Patients study was a multicenter, observational study that included all adult patients admitted to 198 European ICUs between May 1 and May 15, 2002 and followed them until death, until hospital discharge, or for 60 days. Patients were classified depending on whether they had received a blood transfusion at any time during their ICU stay. Results: Of 3,147 patients, 1,040 (33.0%) received a blood transfusion. These patients were older (mean age, 62 vs. 60 yr; P = 0.035) and were more likely to have liver cirrhosis or hematologic cancer, to be a surgical admission, and to have sepsis. They had a longer duration of ICU stay (5-9 vs. 2.5 days; P < 0.001) and a higher ICU mortality rate (23.0 vs. 16.3%; P < 0.001) but were also more severely ill on admission (Simplified Acute Physiology Score II, 40.2 vs. 34.7; P < 0.001; Sequential Organ Failure Assessment score, 6.5 vs. 4.5; P < 0.001). There was a direct relation between the number of blood transfusions and the mortality rate, but in multivariate analysis, blood transfusion was not significantly associated with a worse mortality rate. Moreover, in 821 pairs matched according to a propensity score, there was a higher 30-day survival rate in the transfusion group than in the other patients (P = 0.004). Conclusion: This observational study does not support the view that blood transfusions are associated with increased mortality rates in acutely ill patients.