Propensity score matching
A total of 1,184 pairs were matched according to their
propensity score [see Table S5 and Figure S3 in Additional
file 1]. Transfused patients for whom propensity
score-matched pairs were found had a higher incidence
of chronic renal failure and cirrhosis, were more commonly
unplanned admissions, had greater SAPS II and
SOFA scores and lower hemoglobin concentrations on
admission to the ICU, had higher mortality rates, and
longer ICU and hospital lengths of stay than those for
whom no matched pairs were found (n = 649) [see Table
S6 in Additional file 1]. However, there were no differences
in baseline characteristics or outcomes between the
propensity score-matched patients (Table 4). The mean
hemoglobin concentration prior to transfusion was 8.3 ±
1.8 g/dl in this subgroup. ICU and in-hospital mortality
rates were similar (6.3 vs. 7.3% and 11.8 vs. 12.2%, respectively,
P > 0.2 pairwise) among transfused and non-transfused-
matched pairs.