Effect of Transfusion on Mortality and Other Adverse Events Among Critically Ill Septic Patients: An Observational Study Using a Marginal Structural Cox Model.

OBJECTIVES

RBC transfusion is often required in patients with sepsis. However, adverse events have been associated with RBC transfusion, raising safety concerns. A randomized controlled trial validated the 7 g/dL threshold, but previously transfused patients were excluded. Cohort studies led to conflicting results and did not handle time-dependent covariates and history of treatment. Additional data are thus warranted to guide patient's management.

DESIGN

To estimate the effect of one or more RBC within 1 day on three major outcomes (mortality, ICU-acquired infections, and severe hypoxemia) at day 30, we used marginal structural models. A trajectory modeling, based on hematocrit evolution pattern, allowed identification of subgroups. Secondary analyses were performed into each of them.

SETTING

A prospective French multicenter database.

PATIENTS

Patients with sepsis at admission. Patients with hemorrhagic shock at admission were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Overall, in our cohort of 6,016 patients, RBC transfusion was not associated with death (hazard ratio, 1.07; 95% CI, 0.88-1.30; p = 0.52). However, RBC transfusion was associated with increased occurrence of ICU-acquired infections (hazard ratio, 2.77; 95% CI, 2.33-3.28; p < 0.01) and of severe hypoxemia (hazard ratio, 1.29; 95% CI, 1.14-1.47; p < 0.01). A protective effect from death by the transfusion was found in the subgroup with the lowest hematocrit level (26 [interquartile range, 24-28]) (hazard ratio, 0.72; 95% CI, 0.55-0.95; p = 0.02).

CONCLUSIONS

RBC transfusion did not affect overall mortality in critically ill patients with sepsis. Increased occurrence rate of ICU-acquired infection and severe hypoxemia are expected outcomes from RBC transfusion that need to be weighted with its benefits in selected patients.