Prevalence and clinical characteristics of symptomatic diffuse interstitial lung disease in rheumatoid arthritis in a Spanish population

Abstract

Background and objectivesIn Spain, epidemiological studies of the prevalence of diffuse interstitial lung disease (ILD) in rheumatoid arthritis (RA) are limited. Our objective was to estimate the prevalence of symptomatic ILD in RA and its characteristics in our area. Materials and methodsIn our hospital’s interdisciplinary rheumatology and pulmonology clinic, a prospective longitudinal observational study was designed in which we included RA with respiratory symptoms and ILD confirmed by high resolution computed tomography. ResultsOf the 2729 people with RA in our area, 47 had symptomatic ILD, estimating a prevalence of symptomatic ILD in RA of 1.72% (95% CI 1.26–2.29) with an age at diagnosis of RA of 57.3 ± 13.3 years. It was more frequent in men, 60.6% had a history of smoking, and 84.3% and 84.7% had rheumatoid factor (RF) and anti-cyclic citrullinated peptide (Anti-CCP) antibodies, respectively. The most frequent pattern was usual interstitial pneumonitis (UIP), appearing in 28 (31.1%). Nonspecific interstitial pneumonia (NSIP) was more frequent in women, while the combined pulmonary fibrosis-emphysema (CPFE) syndrome presented exclusively in men. ConclusionsWe have analysed the prevalence of symptomatic RA-ILD in our area, which is lower than expected, probably in relation to the definitions used. We have also described that the UIP pattern is the most frequent in RA in our environment, followed by the NSIP. Lastly, we have analysed the prevalence of CPFE in RA, which reaches 13%, for the first time.