Pattern of pulmonary function test in rheumatoid arthritis patients

Abstract

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by a painful symmetrical peripheral polyarthritis. Extra-articular involvement in RA is a common condition. Pulmonary involvement occurs in 20 to 67 % of RA patients and it is responsible for about 10-20 % of mortality in RA patients.Objectives: To evaluate the extent and pattern of pulmonary involvement in RA patients by using spirometry. Methods: A case control study conducted at the rheumatology unit of Al Sader teaching hospital, forty RA patients [33(82.5%) female and 7(17.5%) male] and sixty apparently healthy subjects {50(83.3%) female and 10(16.7 %) male} were included in the study. All subjects had subjected to a pulmonary function test (PFT) for pulmonary function evaluation using MIR spirolab III. Measured and predicted forced vital capacities (FVC), forced expiratory volume in the first second (FEV1) and FEV1 / FVC ratio were considered as the parameters in this study for both groups.Results: Nine patients were found to have a restrictive pattern of pulmonary function test, while obstructive pattern was found in only one patient. On the other hand, the pulmonary function tests were normal in all of sixty healthy control. The mean of FEV1 in patient group (2.07 ± 0.56L) and of FEV1% (95.8%  25.2) are significantly lower than those in the control group (2.46 ± 0.65 L; 105.3%  13.09). In addition, mean FVC in the patient group (2.35 ± 0.62L) and its mean percentage (92%  22.68) showed a clear significant reduction compared to those in control group (2.71 ± 0.67 L; 100.53  12.12). No significant difference (P = 0.173) has been observed in FEV1 / FVC ratio between patient (88.17  7.47) and control group (89.87  4.99).Conclusions: Different pattern of pulmonary function abnormalities could be manifested in RA patients and the restrictive pattern represents the most common feature. Spirometry is indicated as a baseline assessment and for follow up of RA patient to enhance early detection and management of the pulmonary involvement.