Table 1.
Baseline characteristics of HF patients in the low vs. high iron group.
| 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 |
ID based on ferritin level is defined as ferritin level < 100 ug/L or 100–299 ug/L if TSAT is < 20%.
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.
*Data are shown as percentages, means ± standard deviation, or medians (25th and 75th percentile).