Rationale: Mortality rates from rheumatoid arthritis-associated interstitial lung disease (RA-ILD) are largely unknown.
Objectives: We sought to determine mortality rates from rheumatoid arthritis-associated interstitial lung disease in the United States from 1988 through 2004.
Methods: Using data from the National Center for Health Statistics, we calculated age-adjusted mortality rates from the deaths of persons with rheumatoid arthritis-associated interstitial lung disease, determined the prevalence of interstitial lung disease in all decedents with rheumatoid arthritis, and compared the age and underlying cause of death in these two cohorts of decedents.
Measurements and main results: From 1988 to 2004, there were 39,138,394 deaths in U.S. residents and 162,032 rheumatoid arthritis-associated deaths. Of these deaths, 10,725 (6.6%) met criteria for rheumatoid arthritis-associated interstitial lung. Mortality rates from rheumatoid arthritis fell over the course of this study in both women and men. However, mortality rates from rheumatoid arthritis-associated interstitial lung disease increased 28.3% in women (to 3.1 per million persons in 2004) and declined 12.5% in men (to 1.5 per million persons in 2004). Because the rate of decline in rheumatoid arthritis outpaced rheumatoid arthritis-associated interstitial lung disease in men, the prevalence of rheumatoid arthritis-associated interstitial lung disease increased in both sexes over time.
Conclusions: Clinically significant RA-ILD occurs in nearly 10% of the RA population, and is associated with shortened survival and more severe underlying disease. Whereas overall mortality rates for RA have fallen, those associated with RA-ILD have increased significantly in older age groups.