Association Between Anticoagulation and Survival in Interstitial Lung Disease: An Analysis of the Pulmonary Fibrosis Foundation Patient Registry

Background: Aberrations in the coagulation system have been implicated in the pathogenesis of interstitial lung disease (ILD). Anticoagulants have been proposed as a potential therapy in ILD; however, a randomized controlled trial examining warfarin as a treatment for IPF was terminated early due to increased death rates. This has led some to speculate that warfarin specifically may be harmful in ILD, and use of direct oral anticoagulants (DOACs) could result in superior outcomes.

Research question: The goal of this study was to delineate the relationship between anticoagulation and outcomes in patients with ILD through an analysis of the Pulmonary Fibrosis Foundation Patient Registry.

Study design and methods: An analysis of all patients in the Pulmonary Fibrosis Foundation Patient Registry was performed. Patients were stratified into three groups: no anticoagulation, DOAC use, or warfarin use. Survival was analyzed by using both Kaplan-Meier curves and Cox proportional hazards models.

Results: Of 1,911 patients included in the analysis, 174 (9.1%) were given anticoagulants; 93 (4.9%) received DOACs, and 81 (4.2%) received warfarin. There was a twofold increased risk of death or transplant for patients receiving DOACS; for warfarin, the risk was over two and half times greater. DOACs were not associated with an increased risk of mortality following adjustment for confounding variables. However, even after adjustment, patients given the anticoagulant warfarin remained at increased risk of mortality. In patients with IPF, warfarin was associated with reduced transplant-free survival, but DOACs were not. There was no statistically significant difference in survival between those receiving warfarin and those receiving a DOAC.

Interpretation: The need for anticoagulation is associated with an increased risk for death or transplant in patients with ILD, in both the IPF and non-IPF population. Further research is required to determine if warfarin and DOACs present varying safety profiles in patients with ILD.