The prevalence of rheumatoid arthritis-related interstitial lung disease (RA-ILD) increased over time, according to a recent study that examined the prevalence, incidence, healthcare costs, and mortality associated with RA-ILD. The retrospective cohort analysis used the Truven Health MarketScan Commercial and Medicare Supplemental health insurance databases from 2003 to 2014 and the Social Security Administration death database. Patients with RA-ILD were selected based on diagnoses on medical claims. Outcomes were 1-year prevalence and incidence of RA-ILD among the general enrollee population. Researchers found:
- Prevalence of RA-ILD ranged from 3.2 to 6.0 cases per 100,000 people across the 10-year period and incidence ranged from 2.7 to 3.8 cases per 100,00 people.
- There were 750 incident patients with 5 year of follow-up data. Over that time, 72% had an inpatient admission and 76% had an emergency room visit.
- Healthcare use and costs were stable over time, but substantial.
- RA-ILD was associated with decreased survival.
Raimundo K, Solomon JJ, Olson AL, et al. Rheumatoid-interstitial lung disease in the United States: Prevalence, incidence, and healthcare costs and mortality. J Rheumatol. 2019;46(4):360-369. doi:10.3899/jrheum.171315.
In this study, the authors use several US claims databases to examine the burden of RA-associated ILD. From 2004-2013, RA-ILD incidence was stable though the prevalence is gradually increasing, perhaps due to changes in treatment and prolonged survival of patients with RA-ILD. On the other hand, RA-ILD still carries a considerable morality risk; kin this study, over 1/3 of patients with a new diagnosis of RA-ILD had died within 5 years of the initial recorded diagnosis. The authors also report a significant cost burden associated with RA-ILD, but are not able to directly compare this to the costs of RA by itself. While none of the reported findings are surprising, it is interesting to see the results of prior small studies of RA-ILD borne out in these databases. —Arundathi Jayatilleke, MD