Interstitial lung disease -- a large group of disorders that involve inflammation of the lower respiratory tract and breakdown of the structures that transfer oxygen to the bloodstream -- is prevalent and progressive in patients with rheumatoid arthritis (RA), according to a study utilizing high-resolution computed tomography lung scans.
The prevalence of symptomless interstitial lung disease in rheumatoid arthritis is unknown, Dr. Bernadette R. Gochuico and colleagues note in the Archives of Internal Medicine. Nonetheless, given the availability of new therapeutic options, early identification and treatment may improve outcomes.
The investigators studied 64 patients with RA without lung symptoms like shortness of breath or cough and 10 patients with RA and scarring of the lungs (also called pulmonary fibrosis).
High-resolution computed tomography identified "preclinical" interstitial lung disease in 21 of the 64 RA patients without lung symptoms (33 percent), Gochuico and colleagues report.
Air flow and lung volumes were normal in the interstitial lung disease patients at baseline, but gas exchange was impaired compared with subjects with no interstitial lung disease.
During an average follow-up of 2 years, repeat scanning showed disease progression in 12 individuals with preclinical interstitial lung disease and in 6 with pulmonary fibrosis.
"In this cohort of patients with RA, preclinical interstitial lung disease is prevalent and progressive," Gochuico's team writes. "The natural history of disease resembles that of pulmonary fibrosis."
History of smoking may be a risk factor for development of interstitial lung disease in patients with RA, the investigators note. Two thirds of patients with lung disease and less than one quarter without lung disease had a history of smoking, and the average number of "pack-years" smoked was significantly higher in the lung disease group.
SOURCE: Archives of Internal Medicine, January 28, 2008.
http://archinte.ama-assn.org/cgi/content/short/168/2/159
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