Table 1 Baseline characteristics of the 152 pairs of matched cases and controls

Male sex (n [%])

90 (59)

87 (57)

0.73

Age (years; mean ± SD)^a

60 ± 15

61 ± 16

0.67

Body mass index (kg/m²; mean ± SD)

26 ± 6

26 ± 5

0.91

Current smoking (n [%])

57 (37)

38 (25)

0.02

Pre-existing disease (n [%])

54 (35)

62 (41)

0.34

   Chronic respiratory failure (n [%])

22 (14)

15 (10)

0.22

   Chronic heart failure (n [%])

12 (8)

14 (9)

0.68

   Moderate chronic kidney failure (CrCl >30 ml/minute; n [%])

6 (4)

4 (3)

0.52

   Chronic hepatopathy (n [%])

12 (8)

4 (3)

0.04

   Pre-existing neoplastic disease (n [%])

12 (8)

2 (1)

0.01

   Chronic rheumatic disease (n [%])

13 (9)

30 (20)

0.01

McCabe disease severity score (n [%])

   1

125 (82)

149 (98)

< 0.001

   2

27 (18)

3 (2)

   3

0

0