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Real-world screening for interstitial lung disease in rheumatoid arthritis: the value of spirometry, DLCO, and clinical risk factors Cover

Real-world screening for interstitial lung disease in rheumatoid arthritis: the value of spirometry, DLCO, and clinical risk factors

Open Access
|Apr 2026

Figures & Tables

Figure 1.

Categories of decreased PFT measurements (DLCO, FVC, FEV1) based on z-scores: green represents normal (z-score ≥ −1.645); purple, mildly reduced (−2.5 < z-score < −1.645); orange, moderately reduced (−3.0 < z-score ≤ −2.5); and red, severely reduced (z-score ≤ −3.0).

Figure 2.

Flow chart of rheumatoid arthritis (RA) patients and their investigations: all 106 patients underwent pulmonary function tests (PFT), 44.3% of them had indication for lung high-resolution computed tomography (hrCT) and 51.1% of the latter were diagnosed hrCT-confirmed interstitial lung disease (ILD).

General characteristics of the sample (n = 106)_

women81.1%
age (years)65.3 ± 9.7
BMI (kg/m2)28.1 ± 5.9
smoking (ever)35.8%
ACPA positive73.6%
RF positive76.4%
RA duration at PFT (years)14.1 ± 11.9
ESR at RA diagnosis (mm/h)42 ± 29
CRP at RA diagnosis (mg/L)9.9 (3.5; 23.4)
TJC28 at RA diagnosis8 (4; 13)
SJC28 at RA diagnosis5 (1; 8)
PtGA at RA diagnosis (mm)64 ± 24
PhGA at RA diagnosis (mm)49 ± 26
DAS28 at RA diagnosis4.8 ± 1.4
DAS28 at RA diagnosis5.2 ± 1.2
ESR at PFT (mm/h)31 ± 22
CRP at PFT (mg/L)3.9 (2.0; 11.8)
DAS28 at PFT3.7 ± 1.5
DAS28 at PFT3.5 ± 1.4
Steinbrocker radiographic stage 1 at PFT19.8%
Steinbrocker radiographic stage 2 at PFT45.3%
Steinbrocker radiographic stage 3 at PFT17.9%
Steinbrocker radiographic stage 4 at PFT17.0%
csDMARD at PFT90.6%
duration of MTX exposure at PFT (months)48 (13; 108)
b/tsDMARD47.2%
oral glucorticoids13.2%

Differences of PFT measures among various lung phenotype groups (n = 106)

no dyspnea (n = 98)with dyspnea (n = 8)p
DLCO (%)72 ± 2045 ± 310.018
RF negative (n = 25)RF positive (n = 81)
FVC (%)111 ± 2599 ± 210.046
no X-ray bronchiectasis (n = 103)X-ray bronchiectasis (n = 3)
FVC (%)103 ± 2165 ± 220.029
no glucocorticoids (n = 92)glucocorticoids (n = 14)
FEV1 (%)92 ± 1969 ± 140.021

Pulmonary phenotype at PFT date_

all RA patientsn = 106
dyspnea7.5%
cough0.9%
auscultatory rals21.7%
DLCO (%predicted)69 ± 23
DLCO z score−1.74 (−2.73; −0.90)
FVC (% predicted)102 ± 22
FVC z score0.16 (−0.98; 0.86)
FEV1 (%predicted)89 ± 20
FEV1 z score−0.49 (−1.43; 0.31)
X-ray reticulations29.2%
X-ray bronchiectasis2.8%
X-ray emphysema4.7%
X-ray micro/nodules14.2%

PFT associations and differences among RA patients (n = 106)_

bivariate correlations rhop
DLCOAge−0.3600.001*
DLCOESR at RA diagnosis−0.2590.033*
DLCOESR at PFT−0.2520.020*
FVCAge−0.2630.016*
FVCDuration of MTX exposure−0.2410.037*
FEV1Age−0.3680.025*
FEV1BMI0.6460.007*
FEV1CRP at PFT−0.3170.046*
DOI: https://doi.org/10.2478/rjim-2026-0006 | Journal eISSN: 2501-062X | Journal ISSN: 1220-4749
Language: English
Submitted on: Feb 24, 2026
Published on: Apr 13, 2026
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2026 Oana-Georgiana Dinache, Claudiu C. Popescu, Corina D. Mogoșan, Cătălin Codreanu, Luminita Enache, published by N.G. Lupu Internal Medicine Foundation
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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