Outcomes at 3 and 6 months post-intensive care unit (ICU) discharge for mechanically ventilated COVID-19 survivors and significance of change over time
| Outcome | 3 months | 6 months | p-value |
| Subjects n | 50 | 50 | |
| Days from ICU discharge | 89 (86–93) | 174 (113–133) | |
| Days from symptom onset | 119 (113–183) | 205 (194–222) | |
| Inspiratory muscle strength | |||
| MIP cmH2O | 73 (51.5–102) | 86.5 (67.5–111) | ≤0.001 |
| MIP % predicted | 70 (60–89) | 87.6 (70–99) | ≤0.001 |
| MIP <70% predicted | 24 (48) | 12 (24) | ≤0.001 |
| Diaphragm ultrasound imaging | |||
| Diaphragm thickness mm | 0.20 (0.16–0.28) | 0.24 (0.17–0.28) | 0.051 |
| Diaphragm thickness <LLN | 4 (8) | 1 (2) | 0.100 |
| Diaphragm thickening ratio | 1.54 (1.42–1.72) | 1.65 (1.52–1.79) | 0.009 |
| Diaphragm thickening ratio <LLN | 0 (0) | 0 (0) | |
| Functional capacity | |||
| 6MWD | 442.5 (384–537) | 520 (405–588) | ≤0.001 |
| 6MWD % predicted | 71 (66–82) | 82 (71.5–90) | ≤0.001 |
| 6MWD <70% predicted | 23 (46) | 10 (20) | ≤0.001 |
| SpO2 pre-test | 96 (96–98) | 96 (95–97) | 0.043 |
| SpO2 immediately post-test | 95 (93–96) | 95 (93–97) | 0.223 |
| ΔSpO2 | 2.5 (1–4) | 1 (−0.25–4) | 0.05 |
| Post-test desaturation (ΔSpO2 ≥4%) | 14 (28) | 14 (28) | |
| Breathlessness Borg score | 3 (2–4) | 3 (2–4) | 0.935 |
| Lower limb fatigue Borg score | 1 (0–3) | 2 (0–3) | 0.723 |
| Dyspnoea | |||
| mMRC score | 1 (1–2) | 1 (0.75–1) | ≤0.001 |
| mMRC score grade | ≤0.001 | ||
| 0 | 5 (10) | 12 (24) | |
| 1 | 24 (48) | 27 (54) | |
| 2 | 13 (26) | 8 (16) | |
| 3 | 3 (6) | 1 (2) | |
| 4 | 5 (10) | 2 (4) | |
| Health-related quality of life | |||
| SGRQ total score | 20.53 (9.74–30.70) | 13.05 (3.85–21.38) | ≤0.001 |
| SGRQ symptoms domain | 0.0 (0.0–15.78) | 0.0 (0.0–9.21) | 0.049 |
| SGRQ activity domain | 37.75 (18.73–55.58) | 25.9 (6.07–45.91) | 0.001 |
| SGRQ impact domain | 6.85 (2.42–22.83) | 4.4 (0.0–12.04) | 0.001 |
Data are presented as median (25th–75th percentile) for continuous variables and n (%) for categorical variables. MIP: maximal inspiratory pressure; LLN: lower limit of normality; 6MWD: 6-min walk distance; SpO2: pulse oximeter oxyhaemoglobin saturation; mMRC: modified Medical Research Council; SGRQ: St George's Respiratory Questionnaire. Bold values denote statistical significance p<0.05.