Table 1.

Baseline characteristics for adults hospitalized between 2006 and 2013 before and after propensity matching, stratified by AKI status

CharacteristicBefore MatchingAfter Matching
AKI (n=39,153)No AKI (n=391,006)D ValueAKI (n=31,245)No AKI (n=115,696)D Value
Age, yr
 Mean (SD)69 (16)62 (18)0.3869 (15)69 (16)0.04
Age group, yr, n (%)0.370.03
 18–494663 (12)101,428 (26)3552 (11)14,205 (12)
 50–595463 (14)64,391 (17)4218 (14)15,995 (14)
 60–698359 (21)77,462 (20)6592 (21)24,593 (21)
 70–7910,129 (26)75,320 (19)8244 (26)30,176 (26)
 ≥8010,539 (27)72,405 (19)8639 (28)30,727 (27)
Sex, n (%)0.170.02
 Women19,322 (49)226,001 (58)15,686 (50)59,173 (51)
 Men19,831 (51)165,005 (42)15,559 (50)56,523 (49)
Race/ethnicity, n (%)0.050.02
 White27,941 (71)281,584 (72)22,756 (73)85,386 (74)
 Black4506 (12)33,981 (9)3287 (11)11,754 (10)
 Asian/Pacific Islander4748 (12)48,634 (12)3658 (12)13,093 (11)
 Native American268 (0.7)2655 (0.7)206 (0.7)699 (0.6)
 Other/unknown1690 (4)24,152 (6)1338 (4)4764 (4)
Hispanic ethnicity, n (%)5646 (14)58,425 (15)0.014462 (14)15,495 (13)0.03
Current or former smoker, n (%)20,027 (51)178,832 (46)0.1315,833 (51)58,126 (50)0.01
Prior medical history, n (%)
 Coronary heart disease3493 (9)24,097 (6)0.242690 (9)9754 (8)0.01
 Chronic heart failure7643 (20)28,762 (7)0.684779 (15)14,401 (12)0.14
 Ischemic stroke898 (2)10,118 (3)0.07773 (3)2916 (3)0.01
 Peripheral artery disease2685 (7)15,285 (4)0.362071 (7)6925 (6)0.07
 Atrial fibrillation or flutter5266 (13)35,035 (9)0.284217 (13)14,708 (13)0.04
 Diabetes Mellitus15,555 (40)83,724 (21)0.5411,256 (36)38,820 (34)0.07
 Hypertension30,834 (79)220,419 (56)0.6423,015 (74)83,170 (72)0.05
 Dyslipidemia27,273 (70)207,974 (53)0.4321,314 (68)77,189 (67)0.04
 Cancer9157 (23)70,462 (18)0.207498 (24)27,605 (24)0.00
 Proteinuria15,101 (39)77,139 (20)0.5710,490 (34)32,290 (28)0.16
Preadmission eGFR, ml/min per 1.73 m2, n (%)0.100.08
 >15038 (0.1)249 (0.1)32 (0.1)53 (0.0)
 90–1506269 (16)80,484 (21)5131 (16)21,095 (18)
 60–8911,929 (31)125,959 (32)10,256 (33)41,404 (36)
 45–596947 (18)41,133 (11)5549 (18)20,342 (18)
 30–446030 (15)21,162 (5)4301 (14)13,106 (11)
 15–293164 (8)6297 (2)1754 (6)4107 (4)
 Unknown4776 (12)115,722 (30)4222 (14)15,589 (14)
Preadmission medication use, n (%)
 Angiotensin-converting enzyme inhibitor16,823 (43)100,143 (26)0.4712,753 (41)45,526 (39)0.04
 Angiotensin II receptor blocker4974 (13)31,458 (8)0.313812 (12)13,657 (12)0.02
 Diuretic19,823 (51)119,145 (31)0.5214,998 (48)52,503 (45)0.06
β-Blocker17,353 (44)112,333 (29)0.4113,179 (42)46,701 (40)0.05
 Calcium channel blocker9520 (24)53,340 (14)0.436963 (22)23,662 (21)0.07
 Statin19,373 (50)133,614 (34)0.3815,023 (48)53,697 (46)0.04
Index hospitalization features, n (%)
 Coronary bypass surgery77 (0.2)216 (0.1)0.7758 (0.2)130 (0.1)0.30
 Percutaneous coronary intervention84 (0.2)842 (0.2)0.0069 (0.2)338 (0.3)0.17
 Sepsis6945 (18)22,651 (6)0.763911 (13)11,130 (10)0.18
 Heart failure2746 (7)7972 (2)0.781832 (6)4793 (4)0.22
 ICU stay, n (%)12,273 (31)46,576 (12)0.747494 (24)23,024 (20)0.14
 ICU length of stay, h
  Median (IQR)68 (35–139)7 (22–65)<0.001a53 (29–99)40 (23–69)<0.001a
 Hospital length of stay, d
  Median (IQR)6 (3–10)3 (2–5)<0.001a5 (3–8)4 (2–6)<0.001a
 Laboratory-based acute physiology score
  Median (IQR)27 (9–44)6 (0–20)<0.001a24 (6–41)16 (1–30)<0.001a
  Missing, n (%)13 (0.0)179 (0.0)13 (0.0)32 (0.0)
 Comorbidity point score
  Median (IQR)77 (46–114)52 (26–86)<0.001a75 (44–111)73 (43–108)<0.001a
  Missing, n (%)415 (1)4586 (1)366 (1)1319 (1)
 Predicted mortality score
  Median (IQR)3 (1–7)1 (0–2)<0.001a2 (1–6)2 (1–4)<0.001a
  Missing, n (%)1446 (4)31,026 (8)1337 (4)5730 (5)
 Predicted mortality score categorical, n (%)0.420.10
  <0.1%1774 (5)69,083 (18)1702 (5)6442 (6)
  0.1%–0.4%4083 (10)90,413 (23)3809 (12)16,457 (14)
  0.5%–1.9%9422 (24)105,600 (27)8292 (27)35,639 (31)
  2.0%–4.9%9452 (24)53,410 (14)7503 (24)27,364 (24)
  5.0%–9.9%6654 (17)24,650 (6)4774 (15)14,369 (12)
  10.0%–14.9%2772 (7)8438 (2)1826 (6)4881 (4)
  15.0%–29.9%2621 (7)6927 (2)1590 (5)4018 (4)
  ≥30.0%929 (2)1459 (0.4)412 (1)796 (0.7)
  Unknown1446 (4)31,026 (8)1337 (4)5730 (5)
  • The D value represents the standardized difference in means or proportions with a value >0.10 being significant. ICU, intensive care unit; IQR, interquartile range.

  • a Represents P values and not D values.