Table 1

Characteristics of study participants

All patients (n=7049)No AKI
(n=3896)
Short-duration AKI (n=2303)Long-duration AKI (n=850)P value*
Age (years)41 (26–58)36 (24–53)46 (29–61)53 (35–70)<0.001
Male sex (%)5087 (72)3060 (79)1507 (65)520 (61)<0.001
Race/ethnicity (%)<0.001
 White3685 (52)1894 (49)1273 (55)518 (61)
 Black1167 (17)762 (20)301 (13)104 (12)
 Hispanic1560 (22)906 (23)493 (21)161 (19)
 Asian113 (2)62 (2)43 (2)8 (1)
Blunt mechanism of injury (%)5974 (85)3238 (83)1980 (86)756 (89)<0.001
Injury Severity Score20 (13–29)19 (12–29)22 (13–29)21 (13–29)0.002
Arrival systolic blood pressure (mm Hg)122 (101–142)124 (105–142)120 (98–140)122 (99–144)<0.001
Arrival heart rate (beats/min)97 (81–114)96 (81–114)98 (82–115)95 (80–113)0.02
Arrival creatinine (mg/dL)1.2 (0.9–1.4)1 (0.9–1.2)1.4 (1.2–1.6)1.5 (1.3–1.9)<0.001
Arrival hemoglobin (g/dL)12.9 (11.3–14.4)13.2 (11.5–14.5)12.7 (11–14.1)12.5 (10.9–14)<0.001
Arrival base excess−4 (−1 to −8)−4 (−7 to −1)−5 (−8 to −2)−5 (−9 to −2)<0.001
Emergent operation required (%)2188 (31)1210 (31)719 (31)259 (31)0.9
AKI incidence (%)3153 (45)
AKI on arrival (%)2144 (31)1526 (66)640 (75)<0.001
AKI onset >48 h (%)967 (14)325 (14)23 (6)<0.001
AKI duration0 (0–1)1 (1–2)4 (3–6)<0.001
Highest AKI stage (%)<0.001
 No AKI3896 (55)
 Stage 12082 (30)1953 (85)129 (15)
 Stage 2636 (9)300 (13)336 (40)
 Stage 3435 (6)50 (2)385 (45)
Need for renal replacement therapy (%)158 (2)0158 (19)
LOS <1 week (%)2245 (32)1335 (34)665 (29)245 (29)<0.001
 Discharged (%)1770 (25)1128 (29)474 (21)168 (20)
 Mortality (%)475 (7)207 (5)191 (8)77 (9)
Discharge disposition (%)<0.001
 Home3525 (50)2131 (55)1084 (47)310 (36)
 Rehabilitation1057 (15)609 (16)347 (15)101 (12)
 LTC or SNF1153 (16)504 (13)231 (10)231 (27)
 Death706 (10)303 (8)255 (11)148 (17)
 Other608 (9)349 (9)386 (17)60 (7)
Hospital-free days17 (4–24)18 (7–24)16 (3–22)12 (0–22)<0.001
In-hospital mortality (%)706 (10)303 (8)255 (11)148 (17)<0.001
  • Continuous data presented as median (IQR).

  • *Kruskal-Wallis or χ2 test comparing three AKI groups.

  • AKI, acute kidney injury; LOS, length of stay; LTC, long-term care facility; SNF, skilled nursing facility.