Poor prognosis of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) was found to be associated with the male sex, usual interstitial pneumonia (UIP) pattern, and high rheumatoid factor immunoglobulin A (RF-IgA), according to study results published in Seminars in Arthritis and Rheumatism.
The aim of the study was to determine the impact of demographic and clinical characteristics of patients with RA-ILD on prognosis and outcomes. The retrospective study included patients with RA-ILD (29.3% men; mean age at RA-ILD onset, 64.0±10.3 years) hospitalized at the Changhai Hospital of Shanghai, China, from October 2010 to September 2021. Pulmonary function test and high-resolution computed tomography (HRCT) score were used to assess pulmonary functional impairment before and after treatment. Participants were categorized into progressive and stable RA-ILD groups, and their clinical characteristics, demographics, treatment plans, and laboratory tests were analyzed and compared.
The primary study outcome was pulmonary functional impairment compared with diagnosis time.
Incidences of pulmonary dysfunction and adverse events were also recorded, and clinically relevant variables were noted. Factors related to the progression of ILD were determined using Cox regression analysis.
A total of 75 individuals with RA-ILD were included in the study. The progressive RA-ILD group included 32 individuals (42.7%); all deaths (n=13) occurred in this group.
Univariate analyses showed that smoking (P =.007), the male sex (P =.005), high baseline HRCT scores (P =.004), UIP pattern (P =.001), diffusing capacity of the lungs for carbon monoxide (P =.003), and RF-IgA less than 200 RU/mL (P =.001) were significantly associated with increased risk for disease progression; however, leflunomide was associated with improved prognosis, though this might be a result of examining medications after baseline. Backward stepwise logistic regression showed that UIP pattern, RF-IgA less than 200 RU/mL, and the male sex were significantly associated with worse RA-ILD outcomes.
Limitations to the study included a lack of physical fitness data in certain participants, potential selection bias and reduced generalizability due to the use of a single center, potential prescribing bias, and the small sample size.
The researchers concluded that, “[M]ale, UIP pattern, and RF-IgA [greater than] 200 RU/mL may be poor prognostic markers for patients with RA-ILD” and that RF-IgA has “additional prognostic value . . . in patients with RA-ILD.” They also indicated that future studies were necessary to explore “the clinical, physiological, molecular, and genetic characteristics of progressive RA-ILD…so as to stratify the risk of [patients with] RA-ILD and formulate timely intervention measures.”
Chen N, Diao CY, Gao J, Zhao DB. Risk factors for the progression of rheumatoid arthritis-related interstitial lung disease: clinical features, biomarkers, and treatment options. Published online April 11, 2022. Semin Arthritis Rheum. doi:10.1016/j.semarthrit.2022.152004