Table 1. Baseline characteristics of the study population.
| Characteristic | severely anemic cases | non-severely anemic controls | |
| Demographics | N | 207 | 43 |
| Male | 48.8% (101/207) | 69.8% (30/43) | |
| Age (months) | 14.0 (9.7–26.3) | 20.1 (10.6–28.3) | |
| Hematological status | Hemoglobin (g/dl) | 3.6 (0.8) | 9.7 (1.9) |
| MCHC (g/dl) | 32.60(6.8) | 33.2 (5.4) | |
| MCV (fl) | 82.7 (15.4) | 71.2 (8.0) | |
| Reticulocytes % | 3.6 (2.1–6.7) | 2.3 (1.7–4.3) | |
| Erythropoietin >1000 U/L | 95.6% (108/113) | 0% (0/39) | |
| Iron status | Deficiency of bone marrow iron stores | 30.2% (42/139) | n/a |
| Insufficient erythroblast iron incorporation | 41.4% (48/116) | n/a | |
| Hepcidin (nmol/L) | 0.40 (0.19–2.10) | 1.40 (0.31–5.60) | |
| Ferritin (µg/l) | 404 (157–905) | 50 (12–171) | |
| sTfR (µg/ml) | 13.4 (8.1–22.4) | 12.5 (7.2–17.5) | |
| sTfR-F index | 5.1 (3.1–9.6) | 5.9 (3.1–12.0) | |
| Inflammatory status | Bacteremia | 12.6% (25/198) | 0% (0/20) |
| Malaria | 59.9% (124/207) | 37.2% (16/43) | |
| HIV infected | 7.7% (15/195) | 3.7% (2/43) | |
| CRP>40 mg/L | 81.2% (159/196) | 37.7% (12/31) | |
| Interleukin-6 pg/ml | 41.6 (20.9–142.3) | 25.6 (10.0–67.3 | |
Deficiency of bone marrow iron stores was defined as a bone marrow iron score of 0 or 1; Deficiency of functional bone marrow iron was defined as <30% iron deficient erythroblasts while having replete iron stores [22], [26]; CRP: C-Reactive Protein; HIV: Human Immunodeficiency Virus; MCHC: mean cell hemoglobin concentration; MCV mean corpuscular volume; sTfR: soluble transferrin receptor; sTfR-F index: sTfR-log ferritin index31Normally distributed variables are presented with their mean value (s.d.); skewed variable are presented with their median value (inter quartile range). Malaria was defined as a positive blood slide with concurrent fever (axillary temp >37.5°C), or history of fever within the previous 48 hours.