Table 1 Baseline characteristics of the study sample

Age (years)

69.3 ± 8.1

Sex

 Male

238 (77.5%)

 Female

69 (22.5%)

Baseline body mass index (kg/m²)

24.5 ± 3.0

 <18.5, underweight

6 (2.0%)

 18.5–25, normal

179 (58.3%)

 25–30, overweight

108 (35.2%)

 >30, obese

14 (4.6%)

Body mass index at 1-year follow-up (kg/m²)

24.1 ± 3.0

Smoking status

 Never smoker

98 (31.9%)

 Ever smoker

209 (68.1%)

Baseline FVC (% predicted)

80.8 ± 16.5

Baseline DL_CO (% predicted)

64.9 ± 17.9

FVC decline ≥ 5% (% predicted)

93 (30.3%)

DL_CO decline ≥ 10% (% predicted)

59 (19.2%)

GAP index score (IQR)

3 (2–4)

Antifibrotic agents

 No use

73 (23.8%)

 Use

234 (76.2%)

Pulmonary artery diameter (mm) (IQR)

29 (26–31)

Total IPF extent at baseline CT images (%) (IQR)

12.3 (7.6–18.3)

Fat area at T12-L1 on baseline CT (cm²) (IQR)

191.4 (136.7-255.8)

Muscle area at T12-L1 on baseline CT (cm²) (IQR)

100.8 (84.7-112.5)

Fat area at T12-L1 at the one-year follow-up CT (cm²) (IQR)

165.0 (115.5-226.5)

Muscle area at T12-L1 at the one-year follow-up CT (cm²) (IQR)

100.7 (83.5-113.8)

Interval between pulmonary function test (months) (IQR)

12 (11–13)

Interval between CT scans (months) (IQR)

12 (11–14)

Follow-up duration (months) (IQR)

47 (33–64)

Composite outcome*

146 (47.6%)

 Lung transplantation

15 (4.9%)

 Death

139 (45.3%)