medwireNews: Interstitial lung disease (ILD) is present in nearly 5% of patients with rheumatoid arthritis (RA) and can increase the risk for death, report researchers.
The retrospective cohort study included information from a nationwide Medicare database on 509,787 patients with RA (median age, 72.6 years) who claimed a prescription for a DMARD within a year of diagnosis, between 2008 and 2011.
At baseline, 10,306 patients (2.0%) had ILD, while another 13,372 (2.6%) developed ILD during the median 3 years/person of follow-up. In all, 4.6% of the study participants had prevalent or incident ILD, equating to 7.14 cases per 1000 person–years.
Patients with chronic obstructive pulmonary disease and asthma were significantly more likely to develop ILD during the study period than individuals without these respiratory comorbidities (hazard ratio [HR]=2.00 and 1.57, respectively), as were patients who took glucocorticoids (HR=1.45) or biologics/Janus kinase inhibitors (HR=1.34), men (HR=1.35), and smokers (HR= 1.31).
The researchers suggest that these patients at increased risk for ILD “may be particularly amenable for screening/prevention strategies.”
During the 1,940,404 person–years of follow-up, 21.0% of the study participants died. Deaths occurred in 38.7% of patients who had ILD at baseline, compared with 20.7% of those without ILD, giving corresponding mortality rates of 122.01 versus 54.13 per 1000 person–years.
The risk for death was a significant 1.66 times higher among patients who did versus did not have ILD at baseline, the researchers note in Rheumatology.
They investigated specific causes of death and found that patients with ILD at baseline had a significantly greater risk for respiratory and cancer mortality than those without ILD, with respective HRs of 4.39 and 1.56.
The team points out that for RA patients with and without ILD, cancer mortality was most commonly associated with malignant neoplasms of the respiratory and intrathoracic organs.
“While ours is the first to suggest that RA-ILD may be associated with an increased risk of cancer mortality, previous studies showed that ILD as well as interstitial lung abnormalities detected on chest imaging were each associated with subsequent risk of lung cancer and mortality, similar to our findings,” explain Jeffrey Sparks (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and team.
They say that their results “emphasize that clinically significant RA-ILD is not uncommon,” adding that “[f]urther research is needed to understand which patients may be at risk for developing RA-ILD and strategies are needed to mitigate its excess mortality.”
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