One of the common causes of morbidity in patients with RA is pulmonary involvement. Some studies have shown that the possible abnormal results of pulmonary function tests in rheumatoid disease are higher than usual. We aimed to evaluate the prevalence of spirometric abnormalities in patients with RA.
This case-control study was conducted on 99 patients with RA who referred to a rheumatology clinic in Qazvin, northwest Iran. Sixty five age- and sex-matched healthy controls were recruited as well. History taking, physical examination, laboratory tests and spirometry were performed for the participants. RA severity was assessed according to Disease Activity Score 28 (DAS28). The data were processed using SPSS software version 16. Chi square and student's t test and multiple logistic regressions were used as appropriated.
The mean (±SD) age of the patients was 46 (±10.5) years. The mean (±SD) duration of disease was 4.8 (±5.4) years, and the mean (±SD) DAS28 was 2.5 (±1.1). Dyspnea was the most common respiratory complaint (6.1%). Three (3%) patients had mild restrictive, 2 (2%) patients mild obstructive, and one (1%) patient moderate obstructive diseases. In the control group, only one participant had mild restrictive pulmonary disease (P<0.05). A significant decrease of FEF25 [OR=3.2; 95%CI (1.9-4.5)], FEF50 [OR=2.5; 95% CI (1.7-3.1)], FEF75 [OR=2.3; 95% CI (1.4-2.7)] and FEF25-75 [OR=2.7; 95% CI (1.7-3.5)] was observed in patients compared with the control group. We found no correlation between the patients' age, duration and severity of the disease, and laboratory tests with spirometric indices.
It is recommended that patients with RA be visited on a regular basis and PFT be done for them for the early diagnosis of pulmonary involvement.