Table 2 Outcomes at 6 months, according to study group*

Symptoms

 Anyone of the following symptoms—N (%)

28 (90)

28 (85)

5 (− 11 to 22)

1.67 (0.36 to 7.65)

0.71

 Fatigue—N (%)

17 (55)

18 (55)

0 (− 0.23 to 0.23)

1.01 (0.38 to 2.71)

 > 0.99

 Dyspnea—N (%)

22 (71)

21 (64)

7 (− 15 to 29)

1.4 (0.49 to 4.00)

0.60

 mMRC scale (range 0–4)

2 [1–2]

2 [2–3]

0.17 (− 0.16 to 0.51)

0.25

 Dry cough—N (%)

2 (6)

3 (9)

− 03 (− 18 to 13)

0.69 (0.11 to 4.43)

 > 0.99

 Sore throat—N (%)

0 (0)

2 (6)

− 6 (− 20 to 6)

-

0.49

 Productive cough—N (%)

0 (0)

0 (0)

0 (− 0 to 11)

-

-

 Rhinitis—N (%)

2 (6)

1 (3)

3 (− 10 to 18)

2.21 (0.19 to 25.64)

0.61

 Smell disorder—N (%)

3 (10)

1 (3)

7 (− 7 to 22)

3.43 (0.34 to 34.86)

0.35

 Decreased visual acuity– N (%)

5 (16)

2 (6)

10 (− 6 to 27)

2.98 (0.53 to 16.66)

0.25

 Conjunctival hyperaemia—N (%)

0 (0)

0 (0)

0 (− 0 to 11)

-

-

 Taste disorder—N (%)

2 (6)

2 (6)

0 (14 to 15)

1.07 (0.14 to 8.09)

 > 0.99

 Inappetence—N (%)

1 (3)

2 (6)

− 3 (− 17 to 11)

0.52 (0.04 to 6.00)

 > 0.99

 Diarrhoea—N (%)

4 (13)

0 (0)

13 (0 to 29)

-

0.05

 Myalgia—N (%)

9 (29)

12 (36)

− 7 (− 29 to 15)

0.72 (0.25 to 2.05)

0.60

 Arthralgia—N (%)

5 (16)

18 (55)

− 38 (− 56 to − 15)

0.16 (0.05 to 0.52)

0.002

 Chest pain—N (%)

3 (10)

2 (6)

4 (− 11 to 9)

1.66 (0.26 to 10.68)

0.67

 Sicca syndrome—N (%)

1 (3)

1 (3)

0 (− 12 to 13)

1.07 (0.06 to 17.83)

> 0.99

 Raynaud syndrome—N (%)

0 (0)

0 (0)

0 (− 10 to 11)

-

-

 Skin lesion—N (%)

0 (0)

0 (0)

0 (− 10 to 11)

-

-

 Syncope—N (%)

0 (0)

0 (0)

0 (− 10 to 11)

-

-

 Dizziness—N (%)

1 (3)

0 (0)

3 (− 8 to 16)

-

0.48

 Headache—N (%)

0 (0)

0 (0)

0 (− 10 to 11)

-

-

Forced vital capacity % of predicted

92 [84–104]

88 [80–98]

− 6.03 (− 13.96 to 1.88)

0.22

Forced vital capacity < 80% of predicted—N (%)

4 (13)

7 (22)

− 9 (− 27 to 11)

0.55 (0.14 to 2.11)

0.51

Forced expiratory volume in one second % of predicted

94 [87–108]

93 [80–102]

− 4.95 (− 12.8 to 2.90)

0.31

Forced expiratory volume in one second < 80% of predicted—N (%)

3 (10)

7 (23)

− 13 (− 31 to 7)

0.38 (0.09 to 1.64)

0.30

Forced expiratory volume in one second/Forced vital capacity ratio

0.81 [0.77–0.85]

0.82 [0.79–0.85]

0.02 (− 0.01 to 0.05)

0.47

Forced expiratory volume in one second/Forced vital capacity ratio < 80% of predicted—N (%)

7 (23)

11 (37)

− 14 (− 35 to 9)

1.99 (0.65 to 6.10)

0.27

Maximal (mid-) expiratory flow 25–75—litres per second

1.13 [0.97–1.33]

1.16 [0.95–1.37]

0.02 (− 0.15 to 0.19)

0.95

Total lung capacity % of predicted

90 [85–98]

88 [77–92]

− 6.22 (− 13.22 to 0.88)

0.12

Total lung capacity < 80% of predicted—N (%)

4 (13)

10 (33)

− 20 (− 40 to 2)

0.31 (0.08 to 1.13)

0.13

Diffusing capacity of the lung for carbon monoxide % of predicted

78 [70–85]

76 [67–88]

− 1.41 (− 10.43 to 7.60)

0.67

Diffusing capacity of the lung for carbon monoxide < 80% of predicted—N (%)

15 (52)

19 (63)

− 0.12 (− 0.34 to 0.13)

0.62 (0.22 to 1.76)

0.44

Alveolar ventilation—litres

5.41 [4.32–5.99]

5.45 [4.29–5.86]

0.11 (− 0.50 to 0.72)

0.95

Diffusing capacity of the lung for carbon monoxide/alveolar ventilation ratio

0.94 [0.84–1.02]

0.96 [0.86–1.04]

0.02 (− 0.08 to 0.11)

0.64

Residual volume % of predicted

84 [75–97]

84 [69–91]

− 5.33 (− 15.05 to 4.39)

0.41

Residual volume < 80% of predicted—N (%)

11 (37)

11 (35)

2 (− 22 to 24)

1.05 (0.37 to 2.99)

 > 0.99

Residual volume/total lung capacity ratio % of predicted

90 [83–101]

90 [83–99]

− 0.1 (− 6.42 to 6.22)

0.96

Distance walked—metres

490 [420–540]

510 [438–540]

− 5.23 (− 56.63 to 46.17)

0.82

Percentage of predicted value—%

127 [115–150]

125 [105–144]

− 8.61 (− 24.23 to 7.01)

0.36

Less than lower limit of the predicted value—N (%)

1 (4)

4 (15)

− 10 (− 28 to 7)

0.20 (0.02 to 1.96)

0.18

SpO2 nadir during test—%

94 [91–95]

94 [91–95]

− 0.006 (− 0.02 to 0.01)

0.50

Recovery time to return SpO2 to basal value—minutes

1 [1–2]

2 [1–2]

0.36 (− 0.16 to 0.88)

0.43

Maximum heart rate—beats per minutes

107 [99–116]

103 [99–112]

− 2.17 (− 9.01 to 4.68)

0.46

Recovery time to return heart rate to basal value—minutes

2 [2–3]

2 [2–3]

0.23 (− 0.27 to 0.72)

0.36

BORG scale for dyspnea during test (range 0–10)

4 [2–6]

3 [3–5]

− 0.24 (− 1.43 to 0.95)

0.91

Interruption of test—N (%)

0 (0)

1 (3)

− 3 (− 17 to 8)

-

0.49

EQ-VAS (range 0–100)

78 [69–80]

70 [60–80]

− 4.67 (− 11.39 to 2.05)

0.27

EQ-5D-5L

 Impairment in mobility (mobility > 1)—N (%)

10 (29)

14 (39)

− 10 (− 31 to 11)

0.63 (0.23 to 1.70)

0.45

 Impairment in personal care (personal care > 1)—N (%)

7 (20)

8 (22)

− 2 (− 21 to 17)

0.88 (0.28 to 2.74)

> 0.99

 Impairment in usual activities (usual activities > 1)—N (%)

11 (31)

17 (47)

− 16 (− 36 to 7)

0.51 (0.20 to 1.35)

0.23

 Reported pain or discomfort (pain or discomfort > 1)—N (%)

19 (54)

21 (58)

− 4 (− 26 to 18)

0.85 (0.33 to 2.17)

0.81

 Reported anxiety or depression (anxiety or depression > 1)—N (%)

12 (34)

14 (39)

− 5 (− 26 to 17)

0.82 (0.31 to 2.16)

0.81

PCL-5 (range 0–100)

11 [3–17]

8 [2–17]

0.07 (− 7.37 to 7.51)

0.71

SF-36

 Physical functioning (range 0–100)

85 [39–95]

78 [34–95]

− 4.11 (− 20.00 to 11.78)

0.53

 Limitations due to physical health (range 0–100)

50 [0–100]

50 [0–100]

− 3.53 (− 24.61 to 17.54)

0.68

 Limitations due to emotional problems (range 0–100)

67 [25–100]

100 [33–100]

7.65 (− 12.79 to 28.08)

0.41

 Energy/fatigue (range 0–100)

60 [40–75]

60 [36–74]

− 2.75 (− 13.25 to 7.76)

0.56

 Emotional well-being (range 0–100)

76 [60–88]

78 [61–88]

1.09 (− 8.50 to 10.68)

0.90

 Social functioning (range 0–100)

88 [63–100]

75 [41–88]

− 7.80 (− 20.56 to 4.97)

0.16

 Pain (range 0–100)

85 [55–100]

78 [55–90]

− 4.35 (− 16.50 to 7.79)

0.33

 General health (range 0–100)

60 [45–75]

55 [35–74]

− 3.12 (− 14.12 to 7.88)

0.52

 Health change (range 0–100)

25 [25–50]

38 [25–50]

2.44 (− 10.89 to 15.77)

0.72