Incidence and mortality of obstructive lung disease in rheumatoid arthritis: A population-based study

Objective Pulmonary disease represents an important extraarticular manifestation of rheumatoid arthritis (RA). While the association of RA and interstitial lung disease is widely acknowledged, obstructive lung disease (OLD) in RA is less well understood. We therefore aimed to assess the incidence, risk factors, and mortality of OLD in patients with RA. Methods We examined a population-based incident cohort of patients with RA and a comparison cohort of individuals without RA. OLD was defined using a strict composite criterion. Cox proportional hazards models were used to compare OLD incidence between the RA and comparator cohorts to investigate risk factors and to explore the impact of OLD on patient survival. Results A total of 594 patients with RA and 596 subjects without RA were followed for a mean of 16.3 and 19.4 years, respectively. The lifetime risk of developing OLD was 9.6% for RA patients and 6.2% for subjects without RA (hazard ratio [HR] 1.54, 95% confidence interval [95% CI] 1.01-2.34). The risk of developing OLD was higher among male patients, among current or former smokers, and for individuals with more severe RA. Survival of RA patients diagnosed with OLD was worse compared to those without OLD (HR 2.09, 95% CI 1.47-2.97). Conclusion Patients with RA are at higher risk of developing OLD, which is significantly associated with premature mortality. Effective diagnostic and therapeutic strategies to detect and manage OLD in patients with RA may help to improve survival in these patients.