Baseline characteristics of trial participants
| Characteristic | Group; no. (%) or mean ± SD | Relative difference from placebo,† % | |
|---|---|---|---|
| Iron* n = 102 | Placebo n = 96 | ||
| Age, yr | 36.4 ±9.3 | 37.3 ±9.5 | 2.8 |
| Previous iron deficiency | 60 (58.8) | 51 (53.1) | −9.7 |
| Previous pregnancy | 58 (56.9) | 54 (56.3) | −10.5 |
| Menorrhagia | 46 (45.1) | 37 (38.5) | −14.6 |
| Depression (CAPPS score)‡ | 12.1 ±9.7 | 10.0 ±12.5 | 4.0 |
| Anxiety (CAPPS score)‡ | 11.4 ±8.7 | 9.9 ±13.0 | 13.4 |
| Blood characteristics | |||
| Thyroid stimulating hormone, uU/ml | 1.72 ±1.0 | 1.84 ±1.1 | 6.8 |
| C-reactive protein, mg/L | 2.86 ±5.5 | 2.13 ±3.3 | −27.6§ |
| Hemoglobin, g/dL | 13.5 ±0.9 | 13.6 ±0.8 | 1.2 |
| Hemoglobin < 13.0 g/dL | 32 (31.4) | 17 (17.7) | −43.6§ |
| Ferritin, μg/L | 22.5 ±12.7 | 23.3 ±11.6 | 3.7 |
| Ferritin <15 ug/L | 33 (32.4) | 23 (24.0) | −37.3§ |
| Red blood cells, × 1012/L | 4.47 ±0.31 | 4.50 ±0.31 | 0.9 |
| Mean corpuscular volume, fL | 92.0 ±5.0 | 92.6 ±5.3 | 0.7 |
| Hematocrit, % | 41.0 ±2.7 | 41.6 ±2.6 | 1.5 |
| Transferrin, g/L | 2.67 ±0.49 | 2.63 ±0.51 | −1.5 |
| Soluble transferrin receptor, mg/L | 3.44 ±1.1 | 3.60 ±1.1 | 4.4 |
| Transferrin saturation, % | 12.6 ±25.3 | 12.5 ±24.6 | 2.8 |
| Transferrin saturation ≤ 20% | 38 (37.3) | 41 (42.7) | 14.7 |
| Fatigue,‡ | |||
| CAPPS score for fatigue | 25.4 ±8.6 | 25.0 ±8.7 | −1.5 |
| Global fatigue index, MAF | 37.4 ±6.2 | 37.0 ±5.9 | −0.8 |
| Severity of fatigue, MAF | 7.98 ±0.95 | 7.94 ±0.84 | −0.4 |
| Vitality score, SF-12 | 4.75 ±0.96 | 4.56 ±1.0 | −4.2 |
| Quality of life‡ | |||
| CAPPS score | 48.3 ±22.0 | 50.7 ±21.1 | 4.7 |
| SF-12 | 76.7 ±12.0 | 76.2 ±12.6 | −0.6 |
| Mental score SF-12 | 34.3 ±6.6 | 33.8 ±6.3 | −1.5 |
| Physical score SF-12 | 42.5 ±8.3 | 42.4 ±7.6 | −0.1 |
Note: CAPPS = Current and Past Psychological Scale, MAF = Multidimensional Assessment of Fatigue Scale, SD = standard deviation, SF12 = short-form Self-Reported Health Questionnaire.
↵* Iron = prolonged-release ferrous sulfate.
↵† Calculated as (placebo − iron)/iron (FeSO4).
↵‡ Imputed missing data: CAPPS total: 5 in iron group, 4 in placebo group; CAPPS fatigue: 3 in iron group, 1 in placebo; CAPPS depression: 4 in iron group, 2 in placebo group; CAPPS anxiety: 2 in iron group, 4 in placebo group; MAF global fatigue index: 8 in iron group, 6 in placebo group; MAF severity index: 1 in iron group; SF-12: 2 in iron group; SF-1210: 1 in iron group.
↵§ Considered to be a baseline imbalance.