Respiratory function in rheumatoid arthritis.

In 1948 Ellman and Ball drew attention to the pulmonary manifestations of rheumatoid arthritis.' Nevertheless, until recently little attention has been paid to the possibility of pulmonary dysfunction in an appreciable proportion of patients, despite a normal chest x-ray result.2 The reported incidence of pulmonary involvement in rheumatoid arthritis shows considerable variation, ranging from 1 6% using radiological methods of detection alone,4 to 47% using respiratory function tests in addition to radiology.2 This investigation set out to study respiratory function with particular attention to diffusing capacity for carbon monoxide (DCco) in patients with rheumatoid arthritis and a normal chest x-ray film.