Fibrosing alveolitis in patients with rheumatoid arthritis as assessed by high resolution computed tomography, chest radiography, and pulmonary function tests

BACKGROUND—Fibrosing alveolitis (FA) is a common and serious complication of rheumatoid arthritis (RA). Before the availability of high resolution computed tomographic (HRCT) scanning, it was difficult to diagnose accurately without recourse to biopsy. Prospective studies have reported a prevalence of interstitial lung disease (ILD) of 19-44%. The term ILD used by these authors encompasses a variety of appearances on HRCT scans. This prospective study used HRCT scanning to determine the true prevalence of FA in hospital outpatients with RA, and to study associated clinical characteristics.
METHODS—One hundred and fifty consecutive patients with RA were selected from a hospital outpatient department, irrespective of the presence or absence of chest disease. All underwent a detailed clinical assessment, chest HRCT scanning, and conventional chest radiography within 4 weeks of full pulmonary function tests.
RESULTS—Seventy percent of patients were current or reformed cigarette smokers. Twenty eight (19%) had FA, most frequently of reticular pattern, and 12 of this group (43%) also had emphysematous bullae. None of the previously suggested risk factors for developing FA were confirmed. Fifty four percent of patients with HRCT evidence of FA had bilateral basal chest crackles, 82% had a reduced carbon monoxide transfer factor (TLCO), 14% had restrictive pulmonary function tests, and 14% had bilateral chest radiographic signs of FA.
CONCLUSIONS—HRCT evidence of FA was present in 19% of hospital outpatients with RA. Abnormalities on chest examination or on full pulmonary function tests, even without restrictive changes or chest radiographic abnormalities, should prompt physicians to request a chest HRCT scan when investigating dyspnoea in patients with RA.


Predictors of progression of HRCT diagnosed fibrosing alveolitis in patients with rheumatoid arthritis

Background: Fibrosing alveolitis (FA) is the most serious pleuropulmonary extra-articular feature of rheumatoid arthritis (RA). Features that predict progression of FA in patients with RA have not yet been determined. Objective: To identify clinical features that predict progressive FA in patients with RA. Methods: An unselected cohort of 29 patients with RA and FA confirmed by high resolution computed tomography (HRCT) were studied prospectively for 24 months. Three monthly clinical assessment, four monthly pulmonary function tests, and yearly HRCT scanning was undertaken on these patients. Progressive FA was defined as >15% fall in carbon monoxide transfer factor (TLCO) with evidence of increasing FA on HRCT or death as a result of FA. Results: During 24 months of follow up 10/29 (34%) patients had progressive FA. Progression on HRCT was seen as acute ground glass exacerbations or increasing reticular pattern lung involvement. Progressive FA was associated with the presence of bibasal crackles (p=0.041), TLCO (p=0.001), and extent (p=0.026) and distribution (p=0.031) of lung involvement on HRCT at initial presentation. When multiple logistic regression was used, only TLCO remained significant. Receiver operator curve analysis was employed to identify presenting TLCO of progressive FA. A TLCO <54% of the predicted value demonstrated 80% sensitivity and 93% specificity in predicting progressive FA. Conclusions: A TLCO <54% of the predicted value is a highly specific predictor of disease progression