Women with rheumatoid arthritis (RA) are at increased risk for subsequent diagnosis with chronic obstructive pulmonary disease (COPD) but have a similar risk for being diagnosed with asthma compared with women without RA, according to the results of a prospective cohort study within the Nurses’ Health Study, published in Seminars in Arthritis & Rheumatism.
The investigators identified an incident RA cohort within the Nurses’ Health Study and matched each woman with RA with 10 comparator women without RA based on age and year of index date of RA diagnosis. Women with COPD or asthma at baseline were excluded from participation. Data on all women were obtained via biennial questionnaires and medical records. Marginal structural models were used to establish the independent effect of RA on incident COPD or asthma.
A total of 843 women with RA were identified and were matched with 8399 comparators without RA. Mean age of the participants was 59.8 years; mean follow-up after index date was 18.6±9.0 years in women with RA and 18.8±9.5 years among comparators. Following the index date, 8.1% (68 of 843) of incident COPD cases were reported among women with RA and 5.5% (459 of 8399) among comparators. Moreover, 4.7% (40 of 843) of women with RA reported a new diagnosis of asthma after RA diagnosis vs 3.2% (268 of 8399) of comparators.
Women with RA had an increased risk for COPD (hazard ratio [HR], 1.52; 95% CI: 1.17-1.97) and asthma (HR, 1.55; 95% CI: 1.11-2.16) vs comparators. After adjustment for confounders and time-varying mediators that occurred after the index date, including smoking, RA was significantly associated with COPD (HR, 1.68; 95% CI: 1.36-2.07) but not with asthma (HR, 1.11; 95% CI: 0.59-2.09) vs non-RA comparators. Women with seropositive RA and seronegative RA had a similar increased risk for COPD vs non-RA comparators (HR, 1.60; 95% CI: 1.17-2.19; and HR, 1.62; 95% CI: 1.09-2.40, respectively).
The investigators concluded that women with RA had an increased risk for developing COPD compared with women without RA but had a similar risk for developing asthma. Since this association could not be explained by such lifestyle factors as smoking, which may have occurred before or after RA diagnosis, RA-specific factors may predispose individuals to developing COPD independent of smoking. Screening and early therapeutic intervention for respiratory diseases among patients with RA may help to decrease the respiratory burden of the disease.
Sparks JA, Lin T-C, Camargo CA Jr, et al. Rheumatoid arthritis and risk of chronic obstructive pulmonary disease or asthma among women: a marginal structural model analysis in the Nurses’ Health Study [published online September 18, 2017]. Semin Arthritis Rheum. doi:10.1016/j.semarthrit.2017.09.005