Patient characteristics available at the research visit
| Total, N (%) | Post-COVID-19 breathlessness | Total | OR (95% CI) | ||
| No | Yes | ||||
| Total, N (%) | 611 (49.8) | 615 (50.2) | 1226 | ||
| Discharge to review period, months | 1226 (100.0) | 4.7 (3.4–6.0) | 4.7 (3.3–6.0) | 4.7 (3.4–6.0) | 1.00 (1.00–1.00) |
| Breathlessness at research visit, PSQ | 1226 (100.0) | ||||
| 0 | 462 (75.6) | 0 (0.0) | 462 (37.7) | ||
| 1–2 | 70 (11.5) | 143 (23.3) | 213 (17.4) | ||
| ≥3 | 79 (12.9) | 472 (76.7) | 551 (44.9) | ||
| PHQ-9 total score | 1188 (96.9) | 3.0 (1.0–8.0) | 8.0 (3.0–13.0) | 5.0 (2.0–11.0) | 1.09 (1.07–1.12) |
| GAD-7 total score | 1187 (96.8) | 2.0 (0.0–6.0) | 5.0 (1.0–11.0) | 3.0 (0.0–8.0) | 1.07 (1.05–1.09) |
| PCL-5 total severity score | 1184 (96.6) | 6.0 (2.0–15.0) | 15.0 (5.0–31.2) | 9.0 (3.0–23.0) | 1.03 (1.02–1.04) |
| CRP, mg·L−1 | 800 (65.3) | 4.0 (1.4–5.0) | 4.0 (2.0–5.0) | 4.0 (1.8–5.0) | 1.01 (0.99–1.04) |
| BNP/NT-pro-BNP above threshold | 642 (52.4) | 0.65 (0.32–1.33) | |||
| No | 293 (48.0) | 304 (49.4) | 597 (48.7) | ||
| Yes | 29 (4.7) | 16 (2.6) | 45 (3.7) | ||
| Haemoglobin, g·dL−1 | 861 (70.2) | 14.4 (13.3–15.2) | 14.0 (13.1–15.0) | 14.2 (13.2–15.2) | 0.88 (0.79–0.98) |
| Males | 537 (43.8) | 14.7 (13.9–15.6) | 14.6 (13.6–15.5) | 14.7 (13.8–15.5) | 0.90 (0.79–1.03) |
| Females | 324 (26.4) | 13.5 (12.8–14.3) | 13.4 (12.6–14.0) | 13.4 (12.7–14.1) | 0.80 (0.65–0.99) |
| ISWT distance, m | 737 (60.1) | 440.0 (270.0–615.0) | 350.0 (230.0–540.0) | 380.0 (257.5–570.0) | 0.91 (0.85–0.97)# |
| ISWT, % predicted | 658 (53.7) | 60.5 (42.0–81.9) | 52.5 (35.1–71.2) | 56.3 (37.9–75.9) | 0.99 (0.98–1.00) |
| Oxygen saturations post-ISWT, % | 727 (59.3) | 96.0 (94.0–98.0) | 96.0 (94.0–98.0) | 96.0 (94.0–98.0) | 0.98 (0.94–1.02) |
| Borg leg fatigue score post-ISWT | 722 (58.9) | 2.0 (0.5–3.0) | 3.0 (2.0–4.0) | 3.0 (1.0–4.0) | 1.14 (1.06–1.23) |
| FEV1, L | 748 (61.0) | 2.8 (2.3–3.4) | 2.7 (2.2–3.3) | 2.8 (2.2–3.3) | 0.96 (0.81–1.15) |
| FEV1, % predicted | 683 (55.7) | 93.9 (83.4–105.7) | 89.9 (77.9–101.3) | 91.7 (79.7–103.7) | 1.00 (0.99–1.00) |
| FEV1 <LLN | 683 (55.7) | 1.61 (1.05–2.45) | |||
| No | 274 (85.4) | 284 (78.5) | 558 (81.7) | ||
| Yes | 47 (14.6) | 78 (21.5) | 125 (18.3) | ||
| FVC, L | 746 (60.8) | 3.6 (2.9–4.3) | 3.3 (2.6–4.0) | 3.5 (2.8–4.2) | 0.70 (0.57–0.86) |
| FVC, % predicted | 681 (55.5) | 93.7 (83.0–105.4) | 86.8 (74.5–98.5) | 90.0 (78.2–102.4) | 0.98 (0.97–0.99) |
| FVC <LLN | 681 (55.5) | 2.43 (1.60–3.70) | |||
| No | 276 (86.2) | 260 (72.0) | 536 (78.7) | ||
| Yes | 44 (13.8) | 101 (28.0) | 145 (21.3) | ||
| FEV1/FVC ratio, % | 736 (60.0) | 79.4 (73.9–84.0) | 81.6 (77.3–86.0) | 80.6 (76.0–85.5) | 1.04 (1.02–1.06) |
| FEV1/FVC <LLN | 673 (54.9) | 0.58 (0.28–1.19) | |||
| No | 295 (93.1) | 342 (96.1) | 637 (94.7) | ||
| Yes | 22 (6.9) | 14 (3.9) | 36 (5.3) | ||
| TLCO, mmol·min−1·kPa−1 | 272 (22.2) | 7.6 (6.4–8.7) | 6.8 (5.8–8.3) | 7.3 (6.1–8.4) | 0.94 (0.83–1.07) |
| TLCO, % predicted | 252 (20.6) | 90.1 (78.6–102.7) | 90.7 (74.2–104.2) | 90.7 (76.8–103.2) | 0.99 (0.99–1.00) |
| TLCO <80% predicted | 252 (20.6) | 1.48 (0.79–2.77) | |||
| No | 86 (72.3) | 90 (67.7) | 176 (69.8) | ||
| Yes | 33 (27.7) | 43 (32.3) | 76 (30.2) | ||
| KCO, mmol·min−1·kPa−1·L−1 | 276 (22.5) | 1.5 (1.3–1.6) | 1.5 (1.2–1.7) | 1.5 (1.3–1.6) | 0.49 (0.18–1.29) |
| KCO, % predicted | 259 (21.1) | 103.5 (92.6–108.7) | 99.6 (87.4–112.3) | 101.8 (89.2–110.1) | 0.99 (0.97–1.00) |
| KCO <80% predicted | 259 (21.1) | 1.43 (0.53–3.88) | |||
| No | 112 (92.6) | 127 (92.0) | 239 (92.3) | ||
| Yes | 9 (7.4) | 11 (8.0) | 20 (7.7) | ||
Data are presented as median (interquartile range) or n (%), unless otherwise stated. PSQ: Patient Symptom Questionnaire; PHQ-9: Patient Health Questionnaire-9; GAD-7: General Anxiety Disorder-7; PCL-5: Post Traumatic Stress Disorder Checklist; CRP: C-reactive protein; BNP: B-type natriuretic peptide; NT-pro-BNP: N-terminal pro-BNP; ISWT: incremental shuttle walk test; FEV1: forced expiratory volume in 1 s; LLN: lower limit of normal; FVC: forced vital capacity; TLCO: transfer capacity of the lung for carbon monoxide; KCO: carbon monoxide transfer coefficient. #: refers to the risk of worsening breathlessness for each 100 m achieved.