Protective effect of methotrexate on lung function and mortality in rheumatoid arthritis–related interstitial lung disease: a retrospective cohort study
Kangjoon Kim, Ala Woo, Youngmok Park, Seung Hyun Yong, Su Hwan Lee, Sang Hoon Lee, Ah Young Leem, Song Yee Kim, Kyung Soo Chung, Eun Young Kim, Ji Ye Jung, Young Ae Kang, Young Sam Kim, Moo Suk Park
Abstract
BACKGROUND: Studies on the risk and protective factors for lung function decline and mortality in rheumatoid arthritis-related interstitial lung disease (RA-ILD) are limited. OBJECTIVES: We aimed to investigate clinical factors and medication uses associated with lung function decline and mortality in RA-ILD. METHODS: This retrospective cohort study examined the medical records of patients with RA-ILD who visited Severance Hospital between January 2006 and December 2019. We selected 170 patients with RA-ILD who had undergone at least one spirometry test and chest computed tomography scan. An absolute decline of ⩾10% in the functional vital capacity (FVC) was defined as significant decline in pulmonary function. Data for analysis were retrieved from electronic medical records. RESULTS: Ninety patients (52.9%) were female; the mean age was 64.0 ± 10.2 years. Multivariate logistic regression showed that a high erythrocyte sediment rate level at baseline [odds ratio (OR) = 3.056; 95% confidence interval (CI) = 1.183-7.890] and methotrexate (MTX) use (OR = 0.269; 95% CI = 0.094-0.769) were risk and protective factors for lung function decline, respectively. Multivariate Cox regression analysis indicated that age ⩾65 years (OR = 2.723; 95% CI = 1.142-6.491), radiologic pattern of usual interstitial pneumonia (UIP) or probable UIP (OR = 3.948; 95% CI = 1.522-10.242), baseline functional vital capacity (FVC) % predicted (OR = 0.971; 95% CI = 0.948-0.994), and MTX use (OR = 0.284; 95% CI = 0.091-0.880) were predictive of mortality. CONCLUSION: We identified risk and protective factors for lung function decline and mortality in patients with RA-ILD. MTX use was associated with favorable outcome in terms of both lung function and mortality in our cohort.