Approximately 1 in 20 patients with rheumatoid arthritis (RA) will develop interstitial lung disease (ILD), which is associated with increased all-cause, respiratory and cancer mortality rates, according to study results published in Rheumatology.

Studies have shown that RA-associated ILD (RA-ILD) is associated with worsened quality of life and functional impairment, and increased mortality risk. The objective of the current study was to determine the prevalence, incidence and cause-specific mortality or RA-ILD among Americans 65 years of age or older.

The nationwide cohort study used claims data from Medicare on 509,787 patients with RA (mean age, 72.6 years; 76.2% women). Of these, 10,306 patients (2.0%) were previously diagnosed with RA-ILD by a rheumatologist/pulmonologist. During a median follow-up of 3.0 years, 13,372 patients (2.6%) developed RA-ILD. 


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Mortality rates during a follow-up of 1,940,404 person-years were higher among patients with RA-ILD, compared with mortality risk for those without ILD (38.7% vs. 20.7%; multivariable hazard ratio 1.66; 95% CI, 1.60-1.72).

Compared with patients with RA without ILD, a diagnosis of RA-ILD was associated with an increased risk for respiratory mortality (subdistribution hazard ratio, 4.39; 95% CI, 4.13-4.67) and for cancer mortality (subdistribution hazard ratio, 1.56; 95% CI, 1.43-1.71).

Malignancies of the respiratory and intrathoracic organs were the most common neoplasms in those with RA-ILD and in patients with RA without ILD.

The study had several limitations, including missing data on RA-related autoantibodies, disease severity and smoking habits, observational design, and potential unmeasured confounders.

 “These results emphasize that clinically significant RA-ILD is not uncommon and has a significant impact on mortality. Further research is needed to understand which patients may be at risk for developing RA-ILD and strategies are needed to mitigate its excess mortality,” wrote the researchers.

Disclosure: This clinical trial was supported by Bristol-Myers Squibb. Please see the original reference for a full list of authors’ disclosures.

Reference

Sparks JA, Jin Y, Cho SK, et al. Prevalence, incidence and cause-specific mortality of rheumatoid arthritis-associated interstitial lung disease among older rheumatoid arthritis patients. Rheumatology (Oxford). Published online, Jan 18, 2021. doi: 10.1093/rheumatology/keaa836