Sparks JA, et al. - This article is composed with the goal to explore whether rheumatoid arthritis (RA increases the risk for chronic obstructive pulmonary disease (COPD) or asthma independent of factors occurring before RA onset or mediating these respiratory morbidities after diagnosis, for example, cigarette smoking. The outcome of this prospective cohort study showed that RA was related to increased risk for incident COPD, independent of lifestyle confounders and mediators after diagnosis, including smoking.

Methods

• Within the prospective Nurses’ Health Study (n=121,701 women; 1976-2014), they recognized an incident RA cohort and matched each woman with RA to 10 comparators without RA by age and year at index date of RA diagnosis, excluding women with COPD or asthma at baseline.
• In this study, data were obtained through biennial questionnaires and medical records.
• They utilized marginal structural models to ascertain the independent impact of RA on incident COPD or asthma adjusting for confounders and time-varying mediators through inverse probability weighting.

Results

• In this study, they recognized 843 women with RA, matched to 8,399 comparators without RA.
• Mean age was 59.8 years and mean follow-up after index date was 18.6 years (SD 9.0) for women with RA, and 18.8 years (SD 9.5) for comparators.
• They recognized 68 (8.1%) incident COPD and 40 (4.7%) asthma cases among women with RA, and 459 (5.5%) COPD and 268 (3.2%) asthma cases among comparators.
• RA was related to increased risk of COPD (HR 1.52, 95%CI 1.17-1.97) and asthma (HR 1.55, 95%CI 1.11-2.16) compared to comparators adjusted for the matching factors of age and calendar year at index date.
• After further adjustment for confounders and time-varying mediators occurring after index date, including smoking, RA was significantly related to COPD (HR 1.68, 95%CI 1.36-2.07), but not asthma (HR 1.11, 95%CI 0.59-2.09) compared to non-RA comparators.
• Women with seropositive RA (HR 1.60, 95%CI 1.17-2.19) and seronegative RA (HR 1.62, 95%CI 1.09-2.40) had similar increased risk for COPD compared to non-RA comparators.