Table 1. Comparison between patients with and without preexisting respiratory disease in terms of lung function, exercise performance, and health-related quality of life at the follow-up visit.a .
| Demographic/anthropometric data | Patients with preexisting respiratory disease | Patients without preexisting respiratory disease | p |
|---|---|---|---|
| n = 23 | n = 97 | ||
| Age, years | 53.9 ± 17.1 | 56.7 ± 11.6 | 0.462 |
| Weight, kg | 87.4 ± 19.6 | 87.8 ± 17.4 | 0.926 |
| Height, m | 1.66 ± 0.05 | 1.66 ± 0.12 | 0.954 |
| BMI, kg/m2 | 31.6 ± 6.7 | 31.7 ± 5.5 | 0.918 |
| mMRC dyspnea scale score | 2 (0-4) | 1 (0-3) | 0.210 |
| Spirometry | n = 23 | n = 97 | |
| Number of weeks after COVID-19 diagnosis | 15.9 ± 8.0 | 17.2 ± 5.8 | 0.484 |
| FVC, % predicted | 78.9 ± 16.5 | 87.6 (72.7-98.8) | 0.661 |
| FEV1, % predicted | 76.7 ± 19.2 | 93.6 (83.6-106.6) | 0.194 |
| FEV1/FVC | 0.77 ± 0.11 | 0.87 ± 0.05* | < 0.001 |
| FEV1/FVC < LLN, n (%) | 5 (21.7) | 0* | < 0.001 |
| Plethysmography | n = 23 | n = 95 | |
| TLC, % predicted | 85.7 ± 18.4 | 83.8 (74.5-92.7) | 0.959 |
| TLC < LLN, n (%) | 11 (47.8) | 42 (44.2) | 0.754 |
| FRC, % predicted | 98.8 (71.2-109.5) | 81.7 (69.2-91.6) | 0.255 |
| RV, % predicted | 126.4 ± 59.9 | 94.7 (78.7-110.2)* | 0.019 |
| Diffusing capacity of the lung | n = 23 | n = 95 | |
| DLCO, % predicted | 68.3 ± 22.3 | 83.3 (67.6-93.9) | 0.149 |
| DLCO < LLN, n (%) | 13 (59.1) | 38 (40.0) | 0.104 |
| Impulse oscillometry | n = 14 | n = 62 | |
| Resistance at 5 Hz, % predicted | 187.5 ± 60.8 | 127.5 (105.4-170.1)* | < 0.001 |
| Resistance at 20 Hz, % predicted | 138.8 ± 43.2 | 123.2 ± 34.9 | 0.153 |
| R5-R20, Kpa/L/s | 0.24 ± 0.14 | 0.08 (0.06-0.13) * | 0.004 |
| Reactance at 5 Hz, Kpa/L/s | −0.25 ± 0.15 | −0.11 (−0.15 to −0.08)* | 0.008 |
| Resonance frequency, 1/s | 22.4 ± 7.0 | 16.3 ± 4.3* | 0.008 |
| Area of resonance, Kpa/L | 2.13 ± 1.52 | 0.53 (0.3-1.0)* | 0.011 |
| 6MWT | n = 23 | n = 95 | |
| 6MWD, m | 377.4 ± 117.8 | 410.0 ± 104.0 | 0.201 |
| 6MWD, % predicted | 69.0 ± 20.5 | 74.7 ± 25.1 | 0.329 |
| 6MWD < LLN, n (%) | 14 (60.9) | 37 (38.9) | 0.057 |
| Resting SpO2, % | 94.5 ± 1.9 | 96 (94-97) | 0.568 |
| Final SpO2, % | 91.1 ± 4.7 | 94 (92-96)* | 0.033 |
| Final Borg dyspnea scale score | 3.0 ± 2.4 | 0 (0-3.2) | 0.071 |
| Final Borg leg fatigue scale score | 2 (0-4) | 0 (0-3) | 0.698 |
| Final Borg dyspnea score/6MWD, n/km | 8.1 (0.0-12.6) | 0.0 (0.0-0.9)* | 0.014 |
| SF-36 | n = 16 | n = 70 | |
| Physical functioning | 46.2 ± 27.6 | 42.5 (30-61) | 0.541 |
| Role-physical | 12 (0-81) | 0 (0-75) | 0.637 |
| Bodily pain | 56.9 ± 25.3 | 51.0 (31-74) | 0.689 |
| General health | 56.6 ± 22.8 | 62.0 (45-82) | 0.411 |
| Vitality | 58.7 ± 25.0 | 55 (43-70) | 0.542 |
| Social functioning | 53.1 ± 30.7 | 62 (25-87) | 0.489 |
| Role-emotional | 66 (0-100) | 33.3 (0-75) | 0.116 |
| Mental health | 68.5 ± 24.4 | 58.4 ± 24.2 | 0.139 |
| Psychological symptoms | n = 16 | n = 70 | |
| Beck Anxiety Inventory | 18.3 ± 16.6 | 11.5 (4-24.2) | 0.584 |
| Beck Depression Inventory | 8.5 (6.5-15.5) | 9.0 (5.2-17.4) | 0.934 |
| PCL-C | 25.0 (23-31) | 28.0 (22.5-40) | 0.328 |
mMRC: modified Medical Research Council; LLN: lower limit of normal (i.e., below the 5th percentile); FRC: functional residual capacity; R5-R20: resistance at 5 Hz-resistance at 20 Hz; 6MWT: six-minute walk test; 6MWD: six-minute walk distance; SF-36: Medical Outcomes Study 36-Item Short-Form Health Survey; and PCL-C: Posttraumatic Stress Disorder Checklist, Civilian Version. aData presented as mean ± SD, median (IQR), or n (%). *Values of p < 0.05.