For a study, researchers sought to determine the demographic, lifestyle, and serologic risk factors for isolated rheumatoid arthritis (RA)-associated bronchiectasis (RA-BR) that was not caused by interstitial lung disease (ILD).

They conducted a case-control study with RA patients from the Mass General Brigham Biobank. To identify RA-BR cases and controls with RA and RA-related lung illness, they analyzed the records of all patients with RA who met the 2010 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria with computed tomography (CT) chest imaging. The CT chest imaging conducted closest to enrolment for each patient was independently examined by two radiologists for the existence of RA-related lung disorders. Clinical and radiologic evidence of RA-BR was present in all cases, with no interstitial lung abnormalities on imaging. The controls had RA but no bronchiectasis or ILD. Using multivariable logistic regression, they investigated the relationships between demographic, lifestyle, and serologic variables and RA-BR.

They found 57 instances of isolated RA-BR and 360 RA controls who did not have RA-related lung illness. In multivariable models, RA-BR was associated with older age at RA onset (OR 1.37 per 10 years, 95% CI 1.02-1.82), a lower BMI at RA diagnosis (OR 0.94 per kg/m2, 95% CI 0.89-0.99), seropositive RA (OR 3.96, 95% CI 1.84-8.53), positive rheumatoid factor (OR 4.40, 95% CI 2.14-9.07), and positive anticyclic citrullinated peptide (OR 3.47, 95% CI 1.65–7.31). Higher titers of RA-related autoantibodies were linked to an increased risk of RA-BR. 

Seropositivity, being older at the time of RA diagnosis, and having a lower BMI at the time of RA start were all linked to isolated bronchiectasis in RA that ILD did not cause. The findings added to the list of possible risk factors for RA-BR and point to a pathogenic relationship between airway inflammation and RA-related autoantibodies.