Table 1 Patient characteristics and intensity and frequency of cough

Age, years, mean ± SD

69.4 ± 8.9

66.5 ± 11.4

71.3 ± 7.5

0.185

Male sex, n (%)

56 (80)*

13 (27)

7 (70)

< 0.001

Current smoker, n (%)

9 (13)

1 (2)

0 (0)

0.082

Pack-years of smoking, median (IQR)

40 (16–52)

0 (0–15)^†

16 (4–35)

< 0.001

Body mass index^a, mean ± SD

24.1 ± 3.3

23.1 ± 3.6

23.2 ± 2.0

0.279

FSSG score, median (IQR)

3 (1–7)

6 (2–12)^†

4 (1–4)

0.010

MRC chronic dyspnoea scale, median (IQR)^b

1 (1–2)

1 (1–2)

1 (1–3)

0.824

 FEV₁

82.9 (74.3–94.4)

94.2 (85.6–107.8)^†

87.6 (78.8–90.1)

0.012

 FVC

85.2 (74.2–97.3)

93.6 (80.2–106.1)

73.6 (68.8–93.3)

0.090

 TLC

70.1 (64.3–85.8)

97.1 (79.8–104.1)^†‡

68.5 (54.4–72.1)

< 0.001

 D_LCO

49.2 (38.8–58.9)

55.2 (48.1–66.6)^†

56.0 (37.2–62.9)

0.024

Composite Physiologic Index, median (IQR)^c

43.2 (30.5–52.8)

34.8 (31.1–47.5)

43.5 (34.5–51.2)

0.157

 Glucocorticoid

9 (13)*

30 (61)

4 (40)

< 0.001

 Antifibrotic agent

21 (30)*

0 (0)

2 (20)

< 0.001

 Proton pump inhibitor

21 (30)*

26 (53)

4 (40)

0.040

 Intensity

31 (17–55)^§

24 (8–46)

18 (6–20)

0.048

 Frequency

24 (10–46)

13 (5–30)

10 (3–18)

0.060

 Physical

6.1 (5.5–6.4)

6.0 (5.0–6.5)

6.3 (6.0–6.6)

0.311

 Psychological

6.6 (5.9–7.0)

6.3 (5.3–7.0)

6.8 (6.1–7.0)

0.378

 Social

6.8 (6.0–7.0)

6.5 (5.3–7.0)

6.9 (6.0–7.0)

0.539

 Total

19.3 (17.5–20.4)

18.7 (15.4–20.5)

19.6 (18.3–20.6)

0.447