Pragmatic prognostic approach of rheumatoid arthritis-associated interstitial lung disease.

R heumatoid arthritis (RA) affects approximately 1% of the adult population, with female predominance. Pulmonary involvement is common, and may include a variety of manifestations namely RA-associated interstitial lung disease (ILD) [1, 2], pleural disease [3], rheumatoid nodules and airway complications (crico-arytenoid arthritis, bronchiectasis, bronchiolitis [4]). ILD is usually detected in patients already diagnosed with RA (mostly between the ages of 50 and 60 yrs and more commonly in males), but isolated pulmonary disease may precede the onset of articular disease. Clinically significant RA-ILD affects approximately 7% of patients with RA [5], whereas a higher prevalence was found by autopsy studies or prospective screening studies using high-resolution chest tomography (HRCT) [1]. Thus, RA-ILD may affect up to one out of 1,000 adult persons in the general population. When present, it may decrease the survival of patients by 3.5 to 4.9 yrs [6], although the outcome is highly variable, with indolent course and conversely rapid deterioration being reported. Tobacco smoking, a potentially reversible risk factor, increases the incidence and severity of RA [7] through a proposed mechanism of epitope citrullination in a predisposing genetic background [8], increases the risk of severe extra-articular manifestations of RA [5] and might increase the risk of having ILD in patients with RA although conflicting results have been reported [1, 9].