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Table 1 Baseline characteristics according to tertiles of ERI

From: Association between serum alkaline phosphatase and primary resistance to erythropoiesis stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

Variable

ERI tertile

P

Low

Medium

High

n

18

18

17

 

ERI (IU/kg/wk/gHb)

1.4 ± 0.3

2.3 ± 0.2

3.5 ± 0.8

<0.001

ESA dose (IU/kg/wk)a

153 ± 37

233 ± 25

362 ± 79

<0.001

Type of ESA

   

0.8

Erythropoietin

11 (61 %)

12 (67 %)

12 (71 %)

 

Darbepoetin

7 (39 %)

6 (33 %)

5 (29 %)

 

Hemoglobin (g/L)

111 ± 8

102 ± 13

105 ± 10

0.05

Men

10 (56 %)

8 (44 %)

6 (35 %)

0.5

Age (years)

67.7 ± 13

58.4 ± 17.6

60.5 ± 15.5

0.2

Ethnicity

   

0.4

Caucasian

14 (78 %)

14 (78 %)

15 (88 %)

 

Aboriginal or Torres Strait Islander

0

1 (6 %)

0

 

Maori/Pacific Islander

0

1 (6 %)

0

 

Asian

3 (17 %)

2 (11 %)

0

 

Other

1 (6 %)

0

2 (12 %)

 

Cause of kidney disease b

   

0.9

Diabetes

8 (44 %)

8 (47 %)

5 (29 %)

 

Glomerulonephritis

2 (11 %)

1 (6 %)

4 (24 %)

 

Analgesic nephropathy

0

1 (6 %)

0

 

Polycystic kidney disease

1 (6 %)

1 (6 %)

1 (6 %)

 

Reflux nephropathy

1 (6 %)

1 (6 %)

1 (6 %)

 

Renovascular disease

0

1 (6 %)

1 (6 %)

 

Others

6 (33)

4 (24 %)

5 (29 %)

 

Type of dialysis b

   

0.4

Hemodialysis

17 (94 %)

16 (94 %)

17 (100 %)

 

Peritoneal dialysis

1 (6 %)

0

0

 

Pre-dialysis

0

1 (6 %)

0

 

Diabetes mellitusc

10 (67 %)

9 (82 %)

6 (46 %)

0.2

Ischemic heart diseasec

7 (47 %)

4 (36 %)

7 (54 %)

0.7

Congestive heart failurec

2 (13 %)

1 (9 %)

5 (38 %)

0.1

Cerebrovascular diseasec

1 (7 %)

0

3 (23 %)

0.2

Peripheral vascular diseasec

2 (13 %)

4 (36 %)

4 (31 %)

0.4

Smoking status b

   

0.3

Never

9 (50 %)

5 (29 %)

9 (53 %)

 

Former

8 (44 %)

11 (65 %)

5 (29 %)

 

Current

1 (6 %)

1 (6 %)

3 (18 %)

 

Body mass index (kg/m2)

28.6 ± 4.8

30.4 ± 7.4

29.2 ± 7.6

0.7

Body mass index category

   

0.3

Underweight (<18.5 kg/m2)

0

0

0

 

Healthy weight (18.5 – 24.9 kg/m2)

5 (28 %)

4 (22 %)

6 (35 %)

 

Overweight (25 – 29.9 kg/m2)

9 (50 %)

6 (33 %)

3 (18 %)

 

Obese (>30 kg/m2)

4 (22 %)

8 (44 %)

8 (47 %)

 

Hematocrit (%)

34 ± 3

32 ± 5

32 ± 3

0.7

Mean cellular volume (fL)

94.4 ± 7.8

95.3 ± 6.6

94.3 ± 5.9

0.9

Reticulocyte count (109/L)

57 ± 21

74 ± 38

64 ± 31

0.3

Total white cell count (x 109 per L)

6.8 ± 2

6.4 ± 2.1

6.6 ± 1.5

0.9

Platelet count (x 109 per L)d

207 [164, 286]

188 [167, 207]

197 [164, 274]

0.8

Ferritin (μg/L)d

413 [241, 958]

527 [298, 647]

487 [315, 594]

0.9

Transferrin saturation (%)d

26 [20, 30]

22 [17, 30]

23 [22, 29]

0.6

Serum bicarbonate (mmol/L)

23.3 ± 4

22.6 ± 3

23.6 ± 3

0.6

Albumin (g/L)

36 ± 4

35 ± 4

35 ± 5

0.7

Serum alkaline phosphatase (U/L)d

89 [64, 121]

99 [76, 134]

148 [87, 175]

0.054

Gamma-glutamyltransferase (U/L)d

23 [16, 40]

25 [17, 60]

32 [21, 57]

0.4

Alanine transaminase (U/L)d

16 [11, 19]

15 [9, 22]

10 [8, 19]

0.2

Aspartate transaminase (U/L)d

18 [13, 22]

17 [12, 23]

14 [10, 17]

0.3

Lactate dehydrogenase (U/L)

224 ± 57

224 ± 85

265 ± 63

0.2

Albumin-corrected calcium (mmol/L)

2.3 ± 0.2

2.3 ± 0.1

2.2 ± 0.2

0.2

Phosphate (mmol/L)e

1.7 ± 0.5

1.7 ± 0.5

1.7 ± 0.5

0.9

Parathyroid hormone (pmol/L)d,f

17 [9, 35]

33 [17, 42]

32 [16, 65]

0.2

C-reactive protein (mg/L)

3 [2, 21]

12 [4, 28]

15 [7, 31]

0.06

Oxidative stress substudy

    

n

14

13

14

 

Total F2-isoprostanes (pg/mL)d

133 [87, 213]

143 [128, 200]

112 [67, 173]

0.3

Glutathione peroxidise activity (U/L)

177 (13)

181 (10)

174 (14)

0.4

Superoxide dismutase activity (U/mL)d,f

1.97 [1.41, 2.6]

2.01 [1.32, 2.44]

2.22 [1.71, 2.71]

0.7

Protein carbonyls (nmol/mg)d

0.56 [0.46, 0.6]

0.55 [0.46, 0.74]

0.55 [0.51, 0.69]

0.9

  1. aPatients on darbepoetin were converted to an erythropoietin-equivalent dose using a conversion factor of 200:1
  2. b1 missing data from medium ERI tertile
  3. cMissing data- 3, 7 and 4 values missing from low, medium and high ERI tertiles, respectively
  4. dMedian [IQR]
  5. eto convert phosphate level from mmol/L to mg/dL multiply by 3.1
  6. fto convert parathyroid level from pmol/L to pg/mL multiply by 9.4