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Rheumatoid arthritis (RA) is associated with restrictive and obstructive spirometry patterns, with the strongest associations seen for severe patterns, according to a study published online May 13 in Arthritis & Rheumatology.
Lauren Prisco, from Brigham and Women's Hospital in Boston, and colleagues conducted a cross-sectional study to examine the association between RA and pulmonary function measures on spirometry among individuals who underwent spirometry for research purposes. Associations were estimated adjusting for age, sex, body mass index, and smoking status/pack-years.
The researchers identified 2,008 cases of treated RA among 350,776 analyzed individuals with spirometry performed. Compared with controls, RA was associated with lower percentage predicted forced expiratory volume in one second (FEV1), lower percentage predicted forced vital capacity (FVC), and lower FEV1/FVC (ß = −2.93, −2.08, and −0.008, respectively) in multivariable analyses. Independent of confounders, RA was associated with restrictive and obstructive patterns (odds ratios, 1.36 and 1.21, respectively). The strongest associations were seen for RA with severe restrictive and obstructive patterns.
"These results suggest that RA may be associated with obstructive lung disease in addition to the previously known effects on restrictive lung disease," the authors write. "Clinicians should be aware that both restrictive and obstructive abnormalities are more common in patients with RA and not due to smoking."