Rheumatoid arthritis-associated interstitial lung disease: the relevance of histopathologic and radiographic pattern

Interstitial lung disease (ILD) is a frequent extraarticular manifestation of rheumatoid arthritis (RA). While the nonspecific interstitial pneumonia pattern predominates in most forms of connective tissue-associated ILD, studies in patients with RA-associated ILD (RA-ILD) suggest that the usual interstitial pneumonia (UIP) pattern is more common in this patient population. High-resolution CT (HRCT) scans appear accurate in identifying UIP pattern in many patients with RA-ILD. Although the data are limited, UIP pattern appears to predict worse survival in RA-ILD patients. Larger, prospective, multicenter studies are needed to confirm this finding. We propose that the evaluation of patients with RA-ILD should focus on identifying those with UIP pattern on HRCT scans, as these patients are likely to carry a worse prognosis. In patients in whom the underlying pattern cannot be determined by HRCT scanning, surgical lung biopsy should be considered.