Table 2 Patient characteristics comparing those with and without acute kidney injury

Age (years)

72.5 ± 10.0

71.1 ± 10.2

0.070

Sex (male:female)

317 (58.1%): 229 (41.9%)

146 (53.3%): 128 (46.7%)

0.193

Body Mass Index

31.8 ± 6.7

34.4 ± 7.4

<  0.001

 Non-Hispanic White

412 (75.5%)

171 (62.4%)

<  0.001

 Non-Hispanic Black

35 (6.41%)

39 (14.2%)

<  0.001

 Hispanic

16 (2.9%)

8 (2.9%)

0.993

 Asian

8 (1.5%)

3 (1.1%)

0.664

 Tobacco smoking within 1 year

46 (8.4%)

30 (11.0%)

0.240

 Chronic steroid use

22 (4.0%)

10 (3.7%)

0.791

 Diabetes

113 (20.7%)

110 (40.2%)

<  0.001

 Hypertension

418 (76.6%)

241 (88.0%)

<  0.001

 COPD

28 (5.1%)

29 (10.6%)

0.004

 Congestive heart failure

6 (1.1%)

8 (2.9%)

0.058

 Bleeding disorders

27 (5.0%)

20 (7.3%)

0.171

 History of metastatic cancer

2 (0.4%)

1 (0.4%)

0.998

 Anemia

208 (38.1%)

145 (52.9%)

<  0.001

 Dyspnea

56 (10.3%)

47 (17.2%)

0.005

 Chronic kidney disease

76 (13.9%)

84 (30.7%)

<  0.001

 Primary osteoarthritis

524 (96.0%)

252 (92.0%)

0.017

 Total Hip Arthroplasty

198 (36.3%)

95 (34.7%)

0.654

 Total Knee Arthroplasty

348 (63.7%)

179 (65.3%)

0.654

 Bilateral procedure

5 (0.92%)

9 (3.28%)

0.014

 ASA Physical Classification

2.9 ± 0.5

3.0 ± 0.6

0.701

 Operative time (minutes)

91.3 ± 34.8

100.8 ± 42.2

0.001

 Sodium (mEq/L)

139.7 ± 2.9

139.4 ± 3.1

0.114

 BUN (mg/dL)

21.4 ± 10.3

27.2 ± 15.0

<  0.001

 Creatinine (mg/dL)

1.3 ± 1.5

1.5 ± 1.0

0.132

 Albumin (g/dL)

4.0 ± 0.4

3.9 ± 0.4

0.005

 Bilirubin (mg/dL)

0.6 ± 0.5

0.8 ± 1.2

0.205

 AST (units/L)

23.6 ± 1.08

23.2 ± 12.2

0.741

 ALP (units/L)

84.2 ± 33.4

91.2 ± 38.1

0.058

 WBC (×  10⁹ cells/L)

7.5 ± 6.2

7.8 ± 3.3

0.377

 Hematocrit (%)

40.7 ± 4.7

38.5 ± 5.0

<  0.001

 Platelets (× 10⁹ /L)

227.6 ± 60.3

232.4 ± 72.2

0.314

 PTT (sec)

29.8 ± 5.2

29.9 ± 5.5

0.913

 INR

1.1 ± 0.2

1.1 ± 0.3

0.538

 PT (sec)

12.5 ± 3.3

13.2 ± 4.9

0.568