Disease features and survival outcomes in a retrospective cohort of patients with rheumatoid arthritis-associated interstitial lung disease after lung transplantation

BackgroundInterstitial lung disease (ILD) is a leading cause of morbidity and mortality in patients with rheumatoid arthritis (RA). While the disease course of ILD is variable, some patients with RA have a progressive fibrosing ILD phenotype refractory to treatment. Lung transplantation (LTx) represents a life-extending option for patients with end-stage lung disease; however, data on the clinical features and outcomes of these patients are limited.Objectives(1) To characterize the clinical features of RA-ILD patients who received LTx at a high-volume lung transplantation center; (2) To evaluate survival and predictors of mortality in this cohort.MethodsThis retrospective study included all patients with RA-ILD who received LTx between 2004 to 2020 at UCLA. Patient demographics, RA disease features, explant pathology, pulmonary function tests (PFTs), and survival status were extracted from the electronic medical record. Descriptive statistics were used to summarize disease features. A Kaplan-Meier curve was created to evaluate survival, and a Cox proportional hazards model was created to identify predictors of survival.Results42 RA-ILD patients underwent LTx. The majority of patients were male (57.1%), seropositive (91.4%), with a mean RA disease duration of 12.9 years at LTx (Table 1). Over the study period, 16 (36%) patients died. Compared with patients who had survived, deceased patients were slightly older at the time of transplantation (59.0±9.7 vs. 57.3±11.5, respectively), and were more likely to have usual interstitial pneumonia (UIP) in the lung explant (87.7% vs. 56.0%, p <0.05). The median follow up was 2.3 years (IQR 1.3, 4.7), and median survival time was 5.3 years (IQR 2.7, 7.6; Figure 1). In the univariate Cox proportional hazards analysis, there was a relationship between the presence of UIP pathology and increased mortality, although this did not reach significance (HR 7.13, p=0.06).Table 1.Disease features of study cohort*All patients (N=42)Age at LTx58.0±10.7Female18 (42.9)BMI (kg/m2)25.7±4.2Race- Caucasian28 (66.7)Ethnicity- Hispanic11 (26.2)Smoking, ever17 (40.4)Pack years6.5±12.8RA Disease Duration at Time of LTx (years)12.9±11.4ILD Before/Concurrent to RA#12 (28.6)Erosive11 (40.7)Seropositive%32 (91.4)Pathology- UIP28 (68.3)Pathology- NSIP7 (17.0)Pathology- Other13 (31.7)FVC% at Time of LTx46.9±14.0DLCO% at Time of LTx34.4±17.9Post-Transplant Rheumatology Follow-Up20 (47.6)*Values are N(%) or mean ±SD#ILD diagnosis was made within 12 months of RA diagnosis%RF or CCPFigure 1.Kaplan-Meier survival curve for RA-LTx patients from time of LTx to death, or censor. The shaded area represents the 95% confidence interval. Median time to death was 5.3 years (IQR 2.7, 7.6).ConclusionThis single-center study of RA-ILD patients who underwent LTx demonstrated a median survival time comparable to other LTx cohorts.1 There appeared to be a relationship between the presence of a UIP pattern, and increased risk of mortality, though the small sample size may have precluded the ability to reach statistical significance. Future prospective studies are needed to validate these findings. Understanding the disease features of RA patients who undergo LTx may facilitate the early identification of RA patients at the greatest risk of developing progressive fibrosing phenotype.References[1]Savi D, et al. Transplant Proc. 2018.AcknowledgementsDr. Jeffrey Gornbein (biostatistics)Disclosure of InterestsAmir Razmjou: None declared, Elizabeth Volkmann Speakers bureau: Boehringer Ingelheim, Consultant of: Boehringer Ingelheim, Grant/research support from: Boehringer Ingelheim, Kadmon, Horizon, Forbius, Veena Ranganath Grant/research support from: BMS, Mallinckrodt