Demographic and baseline clinical characteristics of the participants
| Characteristics | FCM (n=24) | Placebo (n=24) |
| Age, years | 69.2±8.4 | 68.0±7.0 |
| Sex, n (%) | ||
| Male | 15 (62.5) | 19 (79.2) |
| Female | 9 (37.5) | 5 (20.8) |
| Body mass index, kg/m2 | 25.7±6.1 | 25.4±4.1 |
| Smoking status, n (%) | ||
| Former | 18 (75.0) | 16 (66.7) |
| Current | 6 (25.0) | 7 (29.2) |
| Never | 0 | 1 (4.2) |
| Pack years | 43 (31–67) | 39 (28–67)a |
| Age at COPD onset, years | 57.2±11.3a | 58.2±5.3b |
| Age at smoking initiation, years | 14.8±2.9 | 14.6±3.0a |
| Age at smoking cessation, years | 59.0 ± 6.5c | 57.5±8.7d |
| Exacerbations in previous year, n | 1 (0–3)a | 2 (1–3)b |
| Lung function* | ||
| FEV1, L | 1.16±0.50 | 1.35±0.38 |
| FEV1, % of predicted | 48.0±17.6 | 49.8±16.9 |
| FEV1/FVC, % | 44.8±9.0 | 40.4±10.2 |
| GOLD grade, n (%) | ||
| Mild (I) | – | – |
| Moderate (II) | 9 (37.5) | 10 (41.7) |
| Severe (III) | 10 (41.7) | 10 (41.7) |
| Very severe (IV) | 5 (20.8) | 4 (16.7) |
| Long-acting inhaled therapy, n (%) | ||
| No long-acting treatment | 1 (4) | 1 (4) |
| LAMA only | 4 (17) | 2 (8) |
| LABA/LAMA | 1 (4) | 0 (0) |
| ICS/LABA | 3 (13) | 1 (4) |
| LAMA/ICS/LABA | 15 (63) | 20 (83) |
| Iron parameters | ||
| Iron, µmol/L | 16.1 (11.0–19.3) | 15.2 (13.2–19.5) |
| Ferritin, µg/L | 84.3 (65.1–110.6) | 69.6 (38.5–151.9) |
| Transferrin, g/L | 2.53±0.32 | 2.53±0.31 |
| Transferrin saturation, % | 28.0 (21.3–37.0) | 26.5 (23.0–38.3) |
| Soluble transferrin receptor, nmol/L | 16.2±4.4 | 17.1±5.0 |
| Hepcidin, ng/mL | 20.7 (12.7–29.1) | 17.7 (8.0–25.1) |
| Haematological parameters† | ||
| Haemoglobin, g/L | 145.4±12.1 | 144.1±14.4 |
| Mean corpuscular volume, fL | 90.6±5.3 | 92.3±3.6 |
| Mean cell haemoglobin, pg | 29.9 (29.3–30.7) | 30.4 (30.0–31.8) |
| Inflammatory parameters | ||
| C reactive protein, mg/dL | 2.4 (0.9–4.6) | 3.7 (1.7–8.2) |
| Interleukin-6, pg/mL‡ | 4.48 (3.56–7.03) | 5.87 (4.29–8.81) |
Data are reported as mean±SD if normally distributed, or median (IQR) if non-normally distributed.
Missing data: an=23, bn=22, cn=18, dn=16.
*Pulmonary function testing was performed at the screening visit unless results were available within 1 year prior to the visit.
†For haematological parameters: n=23 in both groups due to error in sample processing.
‡Interleukin-6 results are only reported for values above the assay detection threshold of 3.13 pg/mL (n=11 in the FCM group, n=16 in the placebo group).
COPD, chronic obstructive pulmonary disease; FCM, ferric carboxymaltose; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; ICS, inhaled corticosteroid; LABA, long-acting beta agonist; LAMA, long-acting muscarinic antagonist.