Table 1 Baseline characteristics of patients according to FGF23 quartile.

From: Circulating Fibroblast Growth Factor-23 Levels are Associated with an Increased Risk of Anemia Development in Patients with Nondialysis Chronic Kidney Disease

Variables

FGF23 quartiles

Total

p-value

Quartile 1 (0.0–1.7)

Quartile 2 (1.8–19.6)

Quartile 3 (19.7–34.6)

Quartile 4 (34.7–774.0)

Number

522

522

523

522

2,089

 

Age (years)

52.6 ± 12.4

53.0 ± 12.2

54.6 ± 11.9

54.0 ± 12.4

53.6 ± 12.2

0.04

Sex (Male, %)

321 (61.5)

318 (60.9)

345 (66.0)

291 (55.7)

1,275 (61.0)

0.01

Smoking (n, %)

238 (45.6)

232 (44.8)

262 (50.1)

240 (46.0)

972 (46.5)

0.41

DM (n, %)

140 (26.8)

145 (27.8)

189 (36.1)

236 (45.2)

710 (34.0)

<0.001

HTN (n, %)

491 (94.1)

503 (96.4)

508 (97.1)

506 (96.9)

2,008 (96.9)

0.41

BMI (kg/m2)

24.5 ± 3.2

24.6 ± 3.4

24.7 ± 3.5

24.4 ± 3.5

24.5 ± 3.4

0.65

SBP (mmHg)

127.9 ± 15.7

126.6 ± 14.7

127.7 ± 16.5

132.0 ± 18.3

128.5 ± 16.5

<0.001

DBP (mmHg)

77.1 ± 11.3

76.2 ± 10.8

76.1 ± 10.9

78.0 ± 11.6

94.1 ± 11.7

0.02

MAP (mmHg)

94.0 ± 11.5

93.0 ± 11.0

93.3 ± 11.5

96.0 ± 12.6

76.9 ± 11.2

<0.001

Anemia (n, %)

165 (31.6)

178 (34.1)

253 (48.4)

329 (63.0)

925 (44.3)

<0.001

Charlson comorbidity index

1.9 ± 1.6

2.1 ± 1.6

2.5 ± 1.5

2.8 ± 1.6

2.3 ± 1.6

<0.001

Creatinine (mg/dl)

1.5 ± 0.8

1.5 ± 0.8

1.9 ± 1.1

2.3 ± 1.5

1.8 ± 1.1

<0.001

eGFR (ml/min/1.73 m2)

59.1 ± 30.1

56.8 ± 31.2

45.6 ± 26.7

39.8 ± 28.5

50.3 ± 30.2

<0.001

CKD stage

  1 (n, %)

116 (22.2)

106 (20.3)

61 (11.7)

53 (10.2)

336 (16.1)

<0.001

  2 (n, %)

137 (26.2)

105 (20.1)

86 (16.4)

64 (12.3)

392 (18.8)

<0.001

  3 (n, %)

183 (35.1)

218 (41.8)

211 (40.3)

170 (32.6)

782 (37.4)

0.006

  4 (n, %)

72 (13.8)

82 (15.7)

133 (25.4)

162 (31.0)

439 (21.0)

<0.001

  5 (n, %)

14 (2.7)

11 (2.1)

32 (6.1)

73 (14.0)

130 (6.2)

<0.001

WBC (x103/mm3)

6.5 ± 2.0

6.6 ± 1.8

6.7 ± 1.9

6.6 ± 2.0

6.6 ± 1.9

0.26

Hemoglobin (g/dl)

13.3 ± 1.8

13.2 ± 1.9

12.8 ± 2.1

12.0 ± 2.0

12.8 ± 2.0

<0.001

Platelet (x103/mm3)

228.8 ± 62.2

231.0 ± 58.0

231.9 ± 59.8

232.2 ± 65.7

231.0 ± 61.5

0.81

Iron (µg/dl)

95.5 ± 35.0

98.1 ± 36.6

93.6 ± 34.6

83.2 ± 32.8

92.6 ± 35.2

<0.001

Ferritin (ng/ml)*

101.5

(58.6–176.0)

91.0

(52.2–161.9)

100.3

(53.6–186.3)

101.0

(49.4–175.2)

98.3

(53.3–175.7)

0.45

Transferrin saturation (%)

32.2 ± 11.7

33.1 ± 12.7

31.8 ± 11.8

29.4 ± 11.9

31.7 ± 12.1

<0.001

Hepcidin (ng/ml)*

11.5

(5.8–22.8)

11.7

(6.1–21.5)

14.4

(7.2–25.8)

16.5

(7.8–30.4)

13.4

(6.6–25.1)

<0.001

Total cholesterol (mg/dl)

176.5 ± 38.3

175.4 ± 37.3

172.8 ± 39.7

173.1 ± 42.2

174.4 ± 39.4

0.37

Albumin (g/dl)

4.2 ± 0.4

4.2 ± 0.4

4.2 ± 0.4

4.1 ± 0.5

4.2 ± 0.4

<0.001

Calcium (mg/dl)

9.2 ± 0.5

9.2 ± 0.5

9.1 ± 0.5

9.0 ± 0.6

9.1 ± 0.5

<0.001

Phosphate (mg/dl)

3.6 ± 0.6

3.6 ± 0.6

3.7 ± 0.6

4.0 ± 0.8

3.7 ± 0.7

<0.001

iPTH (pg/ml)*

44.5

(29.0–68.9)

46.1

(31.2–70.3)

53.0

(35.0–86.3)

69.0

(41.6–121.8)

51.6

(33.2–84.7)

<0.001

1,25(OH)2 vitamin D (pg/ml)

32.1 ± 17.2

29.2 ± 13.3

27.4 ± 12.7

25.7 ± 5.3

28.6 ± 14.4

<0.001

FGF23 (RU/ml)*

0.03

(0.0–0.4)

9.5

(4.8–15.9)

25.5

(22.3–29.8)

52.9

(41.3–75.3)

19.6

(1.7–34.6)

<0.001

CRP (mg/dl)*

0.7 (0.2–1.6)

0.6 (0.2–1.4)

0.6 (0.3–1.6)

0.7 (0.2–2.2)

0.6 (0.2–1.6)

0.04

Proteinuria (g/24 h)*

0.4 (0.1–1.1)

0.5 (0.2–1.2)

0.7 (0.2–1.9)

0.7 (0.3–2.2)

0.5 (0.2–1.6)

<0.001

Treatment

  RAS blockers (n, %)

446 (85.4)

452 (86.6)

436 (83.4)

448 (85.8)

1,782 (85.3)

0.50

  Statin (n, %)

262 (50.2)

273 (52.3)

277 (53.0)

267 (51.1)

1,079 (51.8)

0.84

  Iron replacement (n, %)

50 (9.6)

62 (11.9)

82 (15.7)

113 (21.6)

179 (8.6)

<0.001

  ESA therapy (n, %)

19 (3.6)

27 (5.2)

35 (6.7)

78 (14.9)

167 (7.5)

<0.001

  1. All data are expressed as mean ± SD or *median (and interquartile range)
  2. Abbreviations: FGF23, fibroblast growth factor 23; DM, diabetes mellitus; HTN, hypertension; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; eGFR, estimated glomerular filtration rate; CKD, chronic kidney disease; WBC, white blood cell; iPTH, intact parathyroid hormone; S-Klotho, soluble α-Klotho; CRP, C-reactive protein; RAS, renin-angiotensin system; ESA, erythropoiesis-stimulating agent.
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