Therapy Strategies for ILD in Rheumatoid Arthritis Shifted Over Time

Katinka Albrecht, MD

The yearly prevalence and incidence of interstitial lung disease (ILD) among patients with rheumatoid arthritis (RA) did not change significantly over a 13-year period in Germany, with research identifying an ILD diagnosis in approximately 2% of RA patients per year.

Over time, however, therapies shifted from conventional glucocorticoid, non-steroidal anti-inflammatory drugs (NSAID) and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) to more modern treatment strategies including biological DMARDs and targeted synthetic DMARDs.

“While the yearly prevalence and incidence have not changed markedly, the range of therapies prescribed has enlarged in the more recent years,” wrote corresponding author Katinka Albrecht, MD, Epidemiology and Health Services Research, German Rheumatism Research Centre. “A high amount of prescribed pain medication and opioids indicates unmet needs in these most elderly patients.”

The presence of RA is linked to a threefold to fourfold increased risk of ILD compared with the general population, with significant morbidity and increased mortality. As patients with RA grow older, the absolute numbers of patients with RA-iLD increase, while reported rates have often remained relatively the same.

There is lack of data on the prevalence and incidence of RA-ILD in Germany or medical provision by rheumatology, pulmonology, or general care. The rare nature of the disease means few patients are followed in observational registry studies of patients in rheumatology care.

Here, Albrecht and colleagues collected claims data from the nationwide BARMER statutory health insurance fund from 2007 to 2020. They aimed to examine the occurrence of ILD in people with RA, to provide data on specialist and drug care, and on changes in incidence and treatments over this 13-year period.

Patients with RA-ILD were identified by diagnostic codes, prescriptions of DMARD at any time point prior to or during the index year, and the performance of a lung diagnostic test. Investigators assigned ILD as incident or prevalent with regards to the year of the first diagnosis. Specific treatments were identified using the anatomical therapeutic chemical classification (ATC) and included NSAIDs, glucocorticoids, cs/b/ts DMARDs, analgesics, opioids, and antifibrotics (nintedanib and pirfenidone).

Over the study period, 98,435 (2007) to 142,657 (2020) had an RA diagnosis and 40,686 (2007) to 85,175 (2020) patients had ever been prescribed a DMARD. Prevalent ILD in patients with RA was between 1.6% and 1.7% in 2020, with the highest proportion of 2.2% in 2011–2013 and a slight decline until 2020.

Meanwhile, incident ILD was between 0.13% – 0.21% per year and investigators saw no clear trend over time. They noted it was more frequent in seropositive RA (0.17%), men (0.16%), and in the older age groups (0.14% in >70 years old).

Study data show most people with RA-ILD received glucocorticoids with a decline over time (84% in 2007 to 68% in 2020). The prescription of csDMARDs also decreased over time (83% to 55%), while bDAMRD prescriptions increased from 16% in 2007 to 24% in 2020.

Investigators reported an emergence of tsDMARDs (7%) and antifibrotics (3%) in 2020. A decline in the use of NSAIDs (62% to 38%) was accompanied by an increase in other analgesics (35% to 44%). All years showed 30% of patients received opioids.

The study additionally indicated DMARD therapy was more common in rheumatology care compared to those without rheumatology care, and antifibrotics were rare and almost only prescribed if a pulmonologist was involved. Opioid use was more frequent in general care (39%) but was also common in rheumatology care (32%) followed by pulmonology care (21%).

The study, “Interstitial lung disease in rheumatoid arthritis: incidence, prevalence and related drug prescriptions between 2007 and 2020,” was published in RMD Open.