TABLE 4.

Associations between PRBC age and 24-hour mortality, stratified by PRBC age and volume.

	Total Volume (Units) of Each PRBC Age Category
PRBC Age Category	1–10	11–20	21+
0–7 days	0.82 (0.44–1.51) (n=196)	N/A (n=4)	N/A (n=6)
8–14	1.62 (0.88–2.99) (n=377)	0.92 (0.23–3.65) (n=32)	6.41 (0.88–46.5) (n=13)
15–21	0.72 (0.40–1.30) (n=379)	1.20 (0.36–3.93) (n=26)	1.85 (0.52–6.53) (n=23)
22+	2.56 (1.19–5.48) (n=384)	7.80 (2.99–20.34) (n=64)	4.18 (1.24–14.04) (n=36)

Data in cells reflect adjusted odds ratios for death per additional unit of PRBC received. Odds ratios estimated from a multivariable random effects model adjusted for patient age, sex, race, mechanism of injury, Injury Severity Score, Revised Trauma Score, total PRBC units transfused in the first 24 hours after admission, PROPPR trial treatment group, and accounting for clustering by study site. Patients may be represented in more PRBC = Packed red blood cell.