Post Graduate National Institute of Pharmaceutical Education and Research Guwahati, India
Background: Interstitial lung disease (ILD) is the only complication of rheumatoid arthritis (RA) increasing in prevalence and the leading cause of morbidity and mortality in patients with RA, yet rheumatoid arthritis-interstitial lung disease (RA-ILD) is underrecognized. Costs and ionizing radiation may limit High-Resolution Computed Tomography use in clinical practice, so the prediction of RA-ILD through biochemical predictors can be a prominent option for early detection and management of RA-ILD, especially in patients with risk factors.
Objectives: To assess the potential risk factors and biochemical predictors for early diagnosis of ILD in patients with RA, particularly in the Indian context.
Methods: A cross-sectional study of ongoing prospective study was conducted between July and December 2022. The study included patients diagnosed with RA for ≥6 months (as per the RA classification criteria by ACR/EULAR). Demographic and clinical characteristics were collected from the patient case records and laboratory reports. For the purpose of assessment of risk factors and biochemical predictors of ILD, patients with RA-ILD:RA were considered in a 1:3 ratio. Student t-test and chi-square tests were performed to compare the continuous and categorical variables, respectively.
Results: A total of 299 RA patients were screened, out of which 76 were included based on the study criteria. The female gender was predominant, with 67 (88.1%) patients. Among all the included RA patients, 19 (25%) had RA-ILD, and 57 (75%) had RA. The mean age of RA-ILD patients was significantly higher compared to the RA patients [Mean difference (MD) 4.7, 95% CI 4.3-5.0, P=0.03). There was a statistically significant increase in rheumatoid factor (MD 89.3IU/ml, 95% CI 36.9-141.6, P=0.006) and C-reactive protein (MD 13.8mg/dl, 95% CI 10.7-16.8, P=0.005) in RA-ILD compared to RA. Moreover, there is a positive relationship identified between RA-ILD and xerostomia (P=0.02) and Secondary Sjogren’s syndrome (P=0.009).
Conclusions: The age of RA patients can be a potential risk factor, and elevated rheumatoid factor and C-reactive protein can be biochemical predictors for the development of ILD in RA patients. It is understood that RA patients with xerostomia or Secondary Sjogren’s syndrome had a higher risk of developing ILD.
