Prognosis After Acute Exacerbation in Rheumatoid Arthritis-ILD vs IPF

The prognosis for acute exacerbations of interstitial lung disease (ILD) is significantly better for patients with rheumatoid arthritis (RA)–associated ILD than those with idiopathic pulmonary fibrosis (IPF), according to study findings recently published in Respiratory Medicine.

Investigators for a single-center, retrospective, observational cohort study conducted in Fukuoka, Japan, sought to explore the frequency of AEs in RA-ILD and to compare patient data of those with and without an AE so as to clarify the risk factors for AEs among patients with RA-ILD. The researchers also compared patients’ prognosis post-AE and the cause of death in patients with RA-ILD vs those with IPF.

Data from 913 consecutive patients with RA and 305 individuals with IPF were reviewed. Among the patients reviewed sswith RA, only the 149 patients who were diagnosed with chronic ILD via high-resolution computed tomography (HRCT) findings were included in the study.

Overall, 18.1% (27 of 149) of patients with RA-ILD developed an AE, whereas 27.5% (84 of 305) of those with IPF experienced an AE during the study. The median age at onset of RA was 72 years (range, 39 to 88 years); the median time from RA onset to AE was
70 months (range, 0 to 1420 months). Further, in those with RA-ILD, the median age at onset of AE was 79 years (range, 61 to 88 months), and the median time from diagnosis of ILD to AE onset was 48.5 months (range, 3 to 257 months). The number of patients with a usual interstitial pneumonia (UIP) pattern compared with a non-IUP pattern, as detected on HRCT, was significantly lower among those with RA-ILD vs those with IPF (P <.01).

In patients with RA-ILD and with IPF, the most frequent cause of death was AE. Median survival time after experiencing an AE was 277 days in those with RA-ILD vs 60 days in those with IPF (P =.038).  Investigators also found, per multivariate analysis, that independent risk factors for AE in patients with RA-ILD were hypoalbuminemia (odds ratio [OR], 0.090; 95% CI, 0.011-0.733; P = .012) and percentage of predicted diffusion capacity for carbon monoxide (%DL_CO; OR, 0.810; 95% CI, 0.814-0.964; P <.01).

The present study had several limitations. Because of its single-center design and limited number of patients, results may not be generalizable to entire RA population. Further, selection bias could not be excluded. Although all patients underwent screening for ILD with HRCT, several patients were unable to undergo respiratory function tests; thus, unmeasured variables may influence the study results. Additionally, treatments among patients with RA-ILD (ie, disease-modifying antirheumatic drugs, corticosteroids, and/or immunosuppressive agents) often differ from treatments from those administered to patients with IPF (ie, antifibrotic agents, such as nintedanib and pirfenidone).

The researchers concluded that the prognosis for individuals with RA-ILD after experiencing an AE is better than that of individuals with IPF following an AE.

Reference 

Otsuka J, Yoshizawa S, Kudo K, et al. Clinical features of acute exacerbation in rheumatoid arthritis-associated interstitial lung disease: comparison with idiopathic pulmonary fibrosis. Respir Med. Published online June 4, 2022. doi:10.1016/j.rmed.2022.106898