Prognostic significance of forced vital capacity decline prior to and following antifibrotic therapy in idiopathic pulmonary fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease (ILD). Currently, two antifibrotic drugs are available for reducing forced vital capacity (FVC) decline in IPF. However, many pulmonologists wait before initiating treatment, especially when IPF patients have stable disease. This study aimed to investigate the impact on survival outcome of FVC decline and a slow rate of FVC decline prior to and following treatment with these two antifibrotic drugs. Methods: Out of the 235 IPF patients treated with antifibrotic therapy that were screened, 105 cases were eligible, who then underwent physiological evaluation at 6 months prior to and following antifibrotic therapy. Clinical characteristics and prognostic outcomes were compared among groups, and prognostic factors were evaluated using a Cox proportional hazards analysis. Results: In terms of %FVC decline prior to the therapy and a slow rate of FVC decline, there was no significant difference between stable and worsened groups and responder and non-responder groups, respectively. On the other hand, in terms of %FVC decline (decline >5%) following antifibrotic therapy, the stable/improved group had significantly better prognosis than the worsened group. Prognostic analysis revealed that a stable/improved status following antifibrotic therapy [HR: 0.35 (0.15-0.87)] was significantly associated with a better prognosis. Conclusions: Concerning the FVC decline prior to and following antifibrotic therapy and a slow rate of FVC decline, only the FVC decline following the therapy is associated with a greater survival outcome. An early treatment decision may thus be beneficial for IPF. The reviews of this paper are available via the supplemental material section.