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Table 1 Clinical characteristics of the patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD), which have been classified according to the presence or absence of usual interstitial pneumonia (UIP) pattern in high resolution computed tomography (HRCT)

From: Variable course of disease of rheumatoid arthritis-associated usual interstitial pneumonia compared to other subtypes

Characteristics

RA-ILD

RA-UIP

RA-non-UIP

P-value

(n = 59)

(n = 35, 59.3 %)

(n = 24, 40.7 %)

(UIP vs. non-UIP)

Gender

    

ᅟMale

33 (55.9)

19 (54.3)

14 (58.3)

0.758

ᅟFemale

26 (44.1)

16 (45.7)

10 (41.7)

 

Smokinga

    

ᅟNever

23 (39.7)

14 (41.2)

9 (37.5)

0.778

ᅟEx-smoker

26 (44.8)

14 (41.2)

12 (50.0)

 

ᅟCurrent smoker

9 (15.5)

6 (17.6)

3 (12.5)

 

Age (y)

66 ± 11.1

66 ± 11.9

67 ± 10.0

0.597

Serology

    

ᅟPositive RFb

48 (84.2)

29 (85.3)

19 (82.6)

1.000

ᅟPos. ANAc

8 (17.8)

5 (20.0)

3 (15.0)

0.716

ᅟPos. anti-CCP antibodyd

17 (60.8)

10 (71.4)

7 (63.6)

0.504

Dyspneab

35 (61.4)

25 (73.5)

10 (43.5)

0.022

Coughe

31 (60.8)

17 (60.7)

14 (60.9)

0.991

Inspiratory crackles

41 (69.5)

29 (82.9)

12 (50.0)

0.007

FVC % pred

85 ± 17.0

82 ± 17.1

89 ± 16.5

0.164

DLCO % pred

71 ± 18.1

72 ± 20.7

70 ± 13.3

0.635

Medications

    

ᅟSteroids, ever

54 (91.5)

32 (91.4)

22 (91.7)

1.000

ᅟMTX, ever

35 (59.3)

18 (51.4)

17 (70.8)

0.136

ᅟMTX, when ILD diagnosed

15 (25.4)

6 (17.1)

9 (37.5)

0.078

ᅟBiological drugs, ever

14 (23.7)

7 (20.0)

7 (29.2)

0.416

  1. Data presented as n (percentage) or mean ± SD. P-values calculated using Fisher test, χ2- test or independent T-test
  2. RA-UIP usual interstitial pneumonia (UIP) pattern in patients with rheumatoid arthritis (RA). RA-non-UIP Rheumatoid arthritis patients with other than UIP-pattern interstitial lung disease (ILD). FVC forced vital capacity. DLCO diffusing capacity of the lung for carbon monoxide. % pred: percentage of the predicted value. RF: rheumatoid factor. ANA: anti-nuclear antibodies. MTX: methotrexate. CCP: cyclic citrullinated peptide
  3. adata missing from 1 RA-UIP patient
  4. bdata missing from 2 patients (1 RA-UIP, 1 RA-non-UIP)
  5. cdata missing from 14 patients (10 RA-UIP, 4 RA-non-UIP)
  6. edata missing from 34 patients (21 RA-UIP, 13 RA-non-UIP)
  7. fdata missing from 8 patients (7 RA-UIP, 1 RA-non-UIP)