POS1035 FORCED VITAL CAPACITY TRAJECTORIES AND RISK OF LUNG TRANSPLANT AND ILD-RELATED MORTALITY AMONG PATIENTS WITH RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE (2024)

Abstract

Background: Interstitial lung disease (ILD) is a severe extra-articular manifestation of rheumatoid arthritis (RA). RA-ILD is heterogeneous with about half having a progressive pulmonary disease. The INBUILD trial of nintedanib in progressive fibrotic ILD defined progression using forced vital capacity (FVC) decline, respiratory symptom worsening, or increased fibrosis on chest high-resolution computed tomography imaging (HRCT). (1) However, this definition may not account for different FVC trajectories and has not yet been investigated for clinical outcomes such as lung transplant or ILD-related mortality.

Objectives: We aimed to compare decline in FVC percent predicted (FVCpp) in RA-ILD patients as defined by the: 1) FVCpp component of the progression definition in the INBUILD trial and 2) trajectories of FVCpp change from a group-based trajectory model for risk of the composite of lung transplant or ILD-related death.

Methods: We included patients with RA-ILD from the Mass General Brigham Healthcare system (Boston, MA, USA). All patients met 2010 ACR/EULAR classification criteria for RA and had clinically-apparent RA-ILD. (2) We performed medical record review to collect FVCpp measurements, lung transplant, and ILD-related death outcomes. We used the FVCpp decline definition from the INBUILD trial: relative decline of FVCpp >10% within 24 months. We also performed a group-based trajectory model approach to identify patterns of change in FVCpp from baseline using all FVCpp data. The change from initial FVCpp was fitted and grouped using a maximum likelihood method. Associations between FVCpp decline and trajectory groups with the composite of lung transplant or ILD-related death was estimated using logistic regression, adjusted for age, sex, HRCT ILD pattern, and baseline FVCpp.

Results: We analyzed 172 patients with RA-ILD and multiple FVCpp measurements (mean age 62.2 years [SD 11.3], 62 [36%] male). During a median follow-up of 6.5 years, there were a median of 6 (IQR 3, 9) FVCpp measurements per patient. There were 7 (4%) lung transplants and 44 (26%) ILD-related deaths. A total of 98 (57%) patients had FVCpp decline by >10% within 24 months (INBUILD criteria). These patients with decline had an OR for lung transplant/ILD-related death of 2.82 (95%CI 1.31 to 6.08) compared to those that did not meet the INBUILD definition decline. We identified 3 trajectory groups of change from baseline FVCpp: rapidly declining (n=24/168 [14%]), slowly declining (n=90/168 [54%]), and stable/improving (n=54/168 [32%]), Figure 1. Compared to the stable/improving group, the rapidly declining and slowly declining groups had ORs for lung transplant/ILD-related death of 19.2 (95%CI 4.9 to 75.5) and 4.85 (95%CI 1.71 to 13.8), respectively.

Conclusion: Over half of RA-ILD patients had FVCpp declines according to either the INBUILD definition or trajectory groups. The novel data-driven trajectory group approach identified three groups with different FVCpp trajectories, and the two declining groups had stronger associations with lung transplant or ILD-related death than the definition from the INBUILD trial. The different trajectory groups demonstrate heterogeneity within RA-ILD progression and the importance of PFT monitoring for identifying RA-ILD patients at the highest risk of poor outcomes.

Acknowledgements: NIL.

Disclosure of Interests: None declared.