Table 1 Baseline characteristics of HF patients in the low vs. high iron group.

From: Serum iron: a new predictor of adverse outcomes independently from serum hemoglobin levels in patients with acute decompensated heart failure

Characteristic

Total (n = 615)

Low iron (n = 307)

High iron (n = 308)

P value

Demographic

Age, years

74.3 ± 12.0

76.3 ± 10.8

72.2 ± 12.8

 < 0.0001

Male, %

56.9

53.4

60.4

0.0808

BMI, kg/m2

23.3 ± 4.4

23.0 ± 4.1

23.7 ± 4.6

0.1110

Cause of HF, %

Ischemic

33.5

34.9

32.1

0.4764

Valvular

17.4

18.9

15.9

0.3289

Dilated cardiomyopathy

15.5

13.0

17.9

0.0970

Hypertensive

7.0

6.5

7.5

0.6430

Medical history, %

Hypertension

74.3

76.9

71.8

0.1460

Diabetes mellitus

41.3

47.2

35.4

0.0028

Dyslipidemia

43.1

45.9

40.3

0.1557

Smoking

19.7

16.9

22.4

0.0879

ID based on ferritin level

57.4

40.5

74.6

 < 0.0001

NYHA class on admission, %

III or IV

91.5

91.2

91.9

0.7625

Vital sign at discharge

Systolic blood pressure, mmHg

111.0 ± 17.8

112.0 ± 18.6

110.1 ± 16.9

0.3052

Heart rate, beats/minute

71.4 ± 11.9

71.7 ± 11.7

71.1 ± 12.0

0.5946

Echocardiographic parameters

LVEF, %

46.7 ± 16.0

47.6 ± 16.2

45.9 ± 15.7

0.1872

HFpEF, %

40.7

42.7

38.6

0.2986

LVEDD, mm

52.4 ± 9.3

51.3 ± 9.1

53.4 ± 9.4

0.0017

Laboratory data at discharge

C-reactive protein, mg/dL*

0 .28 (0.10–0.90)

0.50 (0.10–1.30)

0.20 (0.10–0.50)

 < 0.0001

Hemoglobin, g/dL

11.5 ± 2.1

10.8 ± 1.7

12.3 ± 2.2

 < 0.0001

MCV, fl

93.8 ± 6.7

92.6 ± 6.9

95.0 ± 6.2

 < 0.0001

eGFR, mL/min/1.73m2

42.5 ± 22.2

37.2 ± 21.0

47.8 ± 22.1

 < 0.0001

Sodium, mmol/L

137.9 ± 4.0

138.0 ± 4.0

137.9 ± 4.0

0.7095

Plasma BNP, pg/mL*

272 (145–508)

326 (182–626)

225 (124–425)

 < 0.0001

Serum iron, µg/dL*

62.0 (44.0–88.0)

44.0 (33.0–53.0)

88.0 (71.0–110.0)

 < 0.0001

TIBC, µg/dL

287.9 ± 66.2

275.5 ± 71.8

300.3 ± 57.6

 < 0.0001

TSAT, %

24.8 ± 14.7

16.7 ± 12.5

32.8 ± 12.1

 < 0.0001

Ferritin, µg/L

107 (51–203)

86 (40–175)

128 (63–224)

 < 0.0001

Transferrin, mg/dL

224.8 ± 52.2

217.5 ± 54.7

231.4 ± 49.0

0.0005

Medication at discharge, %

ACE inhibitors or ARBs

87.3

85.3

89.3

0.1410

MR blockers

43.6

39.1

48.1

0.0249

β-blockers

74.5

71.7

77.3

0.1103

Diuretics

78.5

79.5

77.6

0.5698

Iron tablets

15.0

9.7

20.2

0.0003

  1. ID based on ferritin level is defined as ferritin level < 100 ug/L or 100–299 ug/L if TSAT is < 20%.
  2. HF heart failure; BMI body mass index; ID iron deficiency; NYHA New York Heart Association; LV left ventricular; EF ejection fraction; HFpEF heart failure with preserved ejection fraction; EDD end-diastolic diameter; MCV mean corpuscular volume; eGFR estimated glomerular filtration rate; BNP B-type natriuretic peptide; TIBC total iron-binding capacity; TSAT transferrin saturation; ACE angiotensin-converting enzyme; ARB angiotensin receptor blocker; MR mineralocorticoid receptor.
  3. *Data are shown as percentages, means ± standard deviation, or medians (25th and 75th percentile).
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