Chronic lung disease in U.S. Veterans with rheumatoid arthritis and the impact on survival

Abstract

Assess the impact of chronic lung diseases (CLD) on survival in rheumatoid arthritis (RA). Among participants in the Veterans Affairs Rheumatoid Arthritis (VARA) Registry, a prospective cohort of U.S. Veterans with RA, we identified CLD and cardiovascular disease (CVD) using administrative and registry data. Demographics, smoking status, RA characteristics including Disease Activity Score in 28 joints (DAS28), and disease-modifying anti-rheumatic drug (DMARD) use were obtained from registry data, which were linked to the National Death Index to obtain vital status. We evaluated associations of CLD with survival using the multivariable Cox regression models. Among a large (n = 2053), male-predominant (91%) RA cohort, 554 (27%) had CLD at enrollment. Mortality risk was increased 1.51-fold (95% CI 1.26-1.81) in RA patients with CLD after multivariable adjustment, a risk that was similar to that observed with CVD (HR CLD alone 1.46 [1.03-2.06]; CVD alone 1.62 [1.35-1.94]). Survival was significantly reduced in those with interstitial lung disease (ILD) as well as other forms of CLD. Mortality risk with methotrexate and biologic use was not different in those with CLD compared to those without (p interaction ≥ 0.15) using multiple exposure definitions and propensity score adjustment. Mortality risk is significantly increased in RA patients with CLD. This risk is attributable not only to ILD but also to other chronic lung conditions and does not appear to be substantially greater in those receiving methotrexate or biologic therapies. Comorbid lung disease should be targeted as a means of improving long-term outcomes in RA.

Keywords: Biologics; Lung disease; Methotrexate; Mortality; Rheumatoid arthritis.

Figure 1.

Comparison of all-cause mortality risk between chronic lung and cardiovascular disease comorbidity. Probability of survival by chronic lung disease (CLD) and cardiovascular disease (CVD) status assessed during the 12 months prior to and following registry enrollment (neither CVD nor CLD [black], CVD only [green], CLD only [blue], both CVD and CLD [red]). The table contained within the figure shows hazard ratios for the association of CVD and CLD with all-cause mortality in multivariable Cox models as well as the null interaction between CVD and CLD