Lung involvement in rheumatoid arthritis, a prospective study.

BACKGROUND

The prevalence of lung involvement in rheumatoid arthritis (RA) remains elusive. Therefore, we set up a multicentric prospective study to investigate the presence of interstitial lung disease (ILD), emphysema, bronchiolitis and nodules in early RA.

METHODS

We recruited patients with RA and a disease duration from 1 to 10 years to screening. Patients underwent comprehensive respiratory evaluation consisting of an environmental questionnaire, high-resolution computed tomography (HRCT), pulmonary function tests (PFTs) and sampling for genetic analysis of common variants associated with RA-ILD. HRCT scans were centrally reviewed.

RESULTS

We included 258 RA patients, median age 56 years old, 71% female and 49% ex- or current smokers. We detected ILD, emphysema and >20% air trapping in 38 (15%), 51 (20%) and 89 (34%) patients, respectively. Older age, male sex, disease activity and lower diffusing capacity of the lung for carbon monoxide ( ) were significantly associated with ILD; and older age, male sex, smoking status and lower were associated with emphysema. No variables were associated with air trapping. Finally, we built stepwise logistic regression models for ILD and emphysema. Older age, higher Disease Activity Score-28, seropositivity for rheumatoid factor, lower and variant were predictors of ILD, whereas the number of pack-years smoking was predictive of emphysema.

CONCLUSIONS

Lung involvement affects a high proportion of early-stage RA patients, constrictive bronchiolitis being the most prevalent, followed by emphysema and ILD. Older age, uncontrolled disease, male sex and lower were associated with both ILD and emphysema, suggesting that we should prioritise screening in these subpopulations.