medwireNews: Study findings suggest that abatacept and tumor necrosis factor (TNF) inhibitors are associated with comparable rates of pulmonary exacerbation among patients with rheumatoid arthritis (RA) and comorbid interstitial lung disease (ILD), chronic obstructive pulmonary disease (COPD), or asthma.
While biologic DMARDs “provide remarkable clinical benefits in RA patients,” they “can pose a potential risk for exacerbations of the comorbid pulmonary conditions by immunosuppression, drug-induced lung injury, or other unknown mechanisms,” explain Seoyoung Kim (Harvard Medical School, Boston, Massachusetts, USA) and co-researchers.
The team drew on two US databases, Medicare and MarketScan, to compare exacerbation rates among RA patients with ILD (n=1999), COPD (n=4555), or asthma (n=2586) who initiated treatment with abatacept or a TNF inhibitor between 2006 and 2015.
Kim and colleagues report that the composite outcome of serious exacerbations requiring hospitalization or an emergency department visit “occurred frequently” across all disease and treatment groups over an average follow-up of 1.0–1.6 years for abatacept-treated patients and 1.4–1.6 years for those given TNF inhibitors.
Among patients with ILD, the incidence rate (IR) of the composite exacerbation outcome per 100 person–years was 6.32 for abatacept-treated patients and 8.59 for those given TNF inhibitors in the Medicare database; the IRs were 3.59 and 11.80, respectively, in the MarketScan cohort.
These results translated into a combined non-significant incidence rate ratio (IRR) of 0.44 for abatacept versus TNF inhibitors after propensity-score fine stratification (PSS) and weighting to account for more than 60 potentially confounding factors.
Similarly, for the other respiratory comorbidities, the PSS-weighted IRRs indicated no significant difference in exacerbation risk associated with abatacept versus TNF inhibitor treatment. IRs ranged from 20.68 to 34.97 per 100 person–years among patients with COPD and from 4.66 to 13.78 per 100 person–years among those with asthma.
Kim and colleagues note in Seminars in Arthritis & Rheumatism that there was also “no substantial difference” in the risk for secondary outcomes including ambulatory exacerbations or respiratory complications among patients with RA–ILD or RA–COPD treated with abatacept versus TNF inhibitors.
The researchers caution that their “estimates are imprecise with wide confidence intervals” due to “the small size of the individual pulmonary condition groups and heterogeneity between the two databases.”
Nonetheless, “the results suggest that an increased risk for pulmonary exacerbations from abatacept is unlikely when compared to similar patients initiating TNF [inhibitors],” they add.
medwireNews is an independent medical news service provided by Springer Healthcare. © 2019 Springer Healthcare part of the Springer Nature group
Semin Arthritis Rheum 2019; doi:10.1016/j.semarthrit.2019.11.010