Table 2.
Concentrations and levels of biomarkers at baseline
| Biomarkers | Total, N = 1450 n (%) | Iron, N = 726 n (%) | Placebo, N = 724 n (%) |
|---|---|---|---|
|
| |||
| Hemoglobin, n = 1450 | |||
| Median (IQR) | 116 (109, 124) | 116 (108, 125) | 117 (109, 124) |
| < 110 g/L | 388 (27%) | 202 (28%) | 186 (26%) |
| Ferritin, μg/L, n = 1450 | |||
| Median (IQR) | 30.1 (19.1, 49.1) | 30.6 (18.9, 47.8) | 30.0 (19.3, 51.0) |
| ≤ 15 | 173 (12%) | 86 (12%) | 87 (12%) |
| C-reactive protein, mg/L, n = 1450 | |||
| Median (IQR) | 4.5 (2.1, 8.0) | 4.7 (2.2, 8.3) | 4.3 (2.1, 7.7) |
| CRP > 5 | 659 (45%) | 348 (48%) | 311 (43%) |
| sTfR, mg/L, n = 3571 | |||
| Median (IQR) | 2.0 (1.1, 2.9) | 2.0 (1.2, 2.8) | 2.0 (1.1, 3.0) |
| > 4.4 | 25 (7%) | 11 (7%) | 14 (8%) |
| sTfR-Ferritin ratio, n = 357 | |||
| Median (IQR) | 1.3 (0.7, 2.1) | 1.4 (0.7, 2.0) | 1.3 (0.8, 2.1) |
| ≤ 1.03 | 226 (63%) | 109 (64%) | 117 (63%) |
| Anemia type, n = 14502 | |||
| Non-anemia | 1062 (73%) | 524 (72%) | 538 (74%) |
| IDA | 181 (13%) | 103 (14%) | 78 (11%) |
| NIDA | 207 (14%) | 99 (14%) | 108 (15%) |
| Anemia—alternative categories, n = 14503 | |||
| Non-anemia | 1062 (73%) | 524 (72%) | 538 (75%) |
| IDA | 207 (14%) | 115 (16%) | 92 (13%) |
| AI | 67 (5%) | 37 (5%) | 30 (4%) |
| Unknown | 114 (8%) | 50 (7%) | 64 (9%) |
AI anemia of inflammation, IDA iron deficiency anemia, IQR interquartile range, NIDA non-iron deficiency anemia
1
A subsample of participants was tested for sTfR
2
In the presence of anemia, IDA was defined as ferritin < 15 μg/L irrespective of inflammation and ferritin < 70 μg/L in the presence of inflammation. Individuals with anemia but not IDA were regarded as NIDA
3
In the presence of anemia, IDA was defined as either (1) ferritin < 15 μg/L, (2) ferritin 15 – < 70 μg/L and CRP > 5 mg/L, or (3) ferritin 15 – < 70 μg/L, CRP ≤ 5 mg/L and sTfR-ferritin ≥ 1.03. AI was defined as either (1) ferritin ≥ 70 μg/L, or (2) ferritin 15 – < 70 μg/L, CRP ≤ 5 mg/L and sTfR-ferritin < 1.0