Transfusion: In critically ill patients may not decrease mortality
Clinical Bottom Line
In critically ill patients, the liberal use of blood transfusions (Hgb 10 g/dl) is not associated with a 5.5% or greater reduction in 30 day mortality.
Citation
A multicenter, randomized, controlled clinical of transfusion requirements in Critical Care
NEJM 1999;340:409-17
Clinical Question
In a critically ill patient, will restrictive blood transfusion practices be equivalent to liberal transfusion practices
Search Terms
"transfusion" and "critical care" and "death"
The Study
- Concealed, unmasked, randomized, controlled clinical trial of equivalency with intention-to-treat analysis. Patients >16 years of age admitted to ICU with <9.0g/dL. Powered to detect a 5.5% or greater decease in 30 day motality.
- Control Group (Liberal strategy of transfusion): (N=420, 416 analyzed); Transfuse to Hgb 10-12 g/dL
- Experimental Group (Restrictive strategy of transfusion): (N=418, 413 analyzed); Transfuse to Hgb 7-9 g/dL.
The Evidence
| Outcome | Time | CER | EER | RRR | ARR [95% CI] | NNT [95% CI] |
|---|---|---|---|---|---|---|
| Death | 30 day | 23% | 19% | 20% | 4.6% [-0.8% - 10.2%] | 22 [NNT 10 to infinity, NNH 35 to infinity] |
| 60 day | 26% | 23% | 14% | 3.8% [-2.1% - 9.5%] | 33 [NNT 11 to infinity, NNH 35 to infinity] |
Comments
- Study terminated early because of decrease in enrollment to below 20% of predicted values
- Study powered to detect a 5.5 % decrease in mortality or greater so can not comment whether transfusion is associated with a smaller decrease in mortality. Since the outcome is mortality, any decrease in mortality may be clinically important
- Those patients who were not enrolled were slightly older, had similar APACHE scores and co-morbid diagnoses except for cardiac disease possibly limiting the generalizability of the results.
- Study had inadequate power to state whether these results apply to patients with significant coronary disease.
- Subgroup analysis suggests that restrictive transfusion may be associated with reduced 30 day mortality in patients less than 55 years of age (5.7% restrictive group and 13% in the liberal transfusion group) and in patients with APACHE II scores less than 20 (8.7% restrictive group and 16.1% liberal group).
CAT created by Martinez E, Pronovost PJ
Appraised By
Pronovost 1999
Expiry Date
2000