To investigate the prevalence of airways obstruction and bronchial reactivity to inhaled methacholine in rheumatoid arthritis patients and unselected controls. The control population consisted of patients attending the rheumatology department for minor degenerative joint problems.
One hundred patients with rheumatoid arthritis (RA) [72 (72%) women, 28 (28%) men; mean (SD) age 58 (10) years] and fifty controls [30 (60%) women, 20 (40%) men; mean (SD) age 56 (9) years] were studied. Detailed medical, smoking and drug histories were taken; skin prick tests were performed to assess atopy and chest and hand radiographs were performed. Spirometry, flow volume loops and gas transfer factor measurement were performed to detect airflow obstruction and methacholine inhalation tests were carried out to assess bronchial reactivity.
There was no significant difference between rheumatoid arthritis patients and the controls in age, sex, smoking status and atopy on skin prick testing (p < 0.05). A significantly higher number of patients with RA had a history of wheeze compared with the controls (18% v 4%, p < 0.05). FEV1, FVC, FEV1/FVC, FEF25-75%, FEF25%, FEF50% and FEF75% were all significantly lower in the rheumatoid arthritis group (p < 0.05). A significantly higher number of patients with RA compared with controls showed bronchial reactivity to inhaled methacholine [55 (55%) v 8 (16%), p < 0.05]. FEV1, FVC, FEV1/FVC, FEF25-75%, FEF25%, FEF50% and FEF75% were all significantly lower among the patients with RA achieving PD20 FEV1 to inhaled methacholine (p < 0.05).
In unselected rheumatoid arthritis patients both airflow obstruction and bronchial reactivity are significantly increased compared with controls.