Progression of Non-IPF ILD Could Be Prognostic for Terminal Outcomes

The progression to terminal outcomes in patients living with idiopathic pulmonary fibrosis (IPF) and non-IPF interstitial lung disease (ILD) varied in patients represented in 2 posters presented during the American Thoracic Society 2026 International Conference, held in Orlando, Florida, from May 17 to May 20, 2026.^1,2 Both posters highlight the need for better patient monitoring to address these potential outcomes as soon as possible.

A first poster focused on the prognosis of patients with non-IPF ILD, which is chronic and progressive but can be affected by underlying causes and the rate of fibrosis. Forced vital capacity percent predicted (FVCpp) acts as a method of measuring the progression in FVC for these patients. The researchers aimed to estimate the trajectory of FVCpp and how it relates to the progression of terminal outcomes.

The Truveta platform was used to identify patients from January 2015 through May 2025 with newly diagnosed non-IPF ILD, which was defined as having 2 or more claims of fibrosis or 1 or more claim for fibrosis with 1 or more claims for an ILD condition within a year of each other. The index date was the first diagnosis of non-IPF ILD, and the follow-up period lasted through the end of clinical activity or death. The baseline value for FVCpp was taken in the 12 months before or 60 days after the index date, and a follow-up FVCpp value was taken after the baseline value. A joint mixed model was used to estimate the trajectory of FVCpp.

There were 5325 patients with a mean age of 69.8 years included in the study, of whom 49.1% were women and whose mean baseline FVCpp was 76.4%. A total of 19.6% of the patients started use of antifibrotics, whereas the remaining population did not take antifibrotics. There were 3 clusters identified: 52.3% were in cluster 1, 24.3% were in cluster 2, and 23.4% were in cluster 3. The mean baseline FVCpp was 75.9 in cluster 1, 73.0 in cluster 2, and 81.0 in cluster 3. The annual FVCpp absolute change was estimated as –0.84% in cluster 1, 2.10% in cluster 2, and –6.30 in cluster 3. Cluster 1 had the highest proportion of patients without terminal outcomes at 5 years with 82.0% compared with 73.1% in cluster 2 and 64.5% in cluster 3.

The researchers concluded that better patient monitoring is needed, as progressions in non-IPF ILD that could be prognostic of terminal outcomes can vary.

This finding was further supported by a separate poster examining patients with IPF,² a severe form of ILD that can also be evaluated through the use of FVCpp. This study aimed to characterize the trajectories of FVCpp both overall and in clusters of patients with similar trajectories, as well as to describe the corresponding terminal outcomes.

The Truveta platform was also used for this study, pulling data from January 2015 through May 2025. At least 2 IPF diagnoses less than a year apart were required for participants in the trial. The first diagnosis of IPF was used as the index date, and the follow-up period lasted through either the end of clinical activity or a real-world terminal outcome. FVCpp was collected at baseline, and 1 or more measures could be used for the follow-up value. None of the patients had used an antifibrotic agent before the index date.

There were 1097 patients with a mean age of 73.9 years who were included in this study. The mean baseline FVCpp was 77.3, and 35.7% of the participants were women. There were 2 clusters identified, with cluster 1 having a mean baseline FVCpp of 91.3 and cluster 2 having a mean baseline FVCpp of 61.4. A total of 84.0% of those in cluster 1 and 71.1% of those in cluster 2 did not experience terminal outcomes after 3 years. The median time to terminal outcomes was 5.5 years in cluster 2 and was not reached in cluster 1.

FVCpp at the time of IPF diagnosis could play a major part in determining the progression to terminal outcomes, based on the results of this study. Both studies demonstrate a need for continued patient monitoring, as baseline FVCpp could be indicative of following outcomes and a signal for earlier intervention.

Reference

1. Kharat A, Boonmak P, Shetty S, et al. Forced vital capacity trajectories and time to outcomes among patients with non-idiopathic pulmonary fibrosis, interstitial lung disease. Presented at: American Thoracic Society 2026 International Conference; May 17-20, 2026; Orlando, FL. Abstract 1793.
2. Kharat A, Boonmak P, Shetty S, et al. Trajectories of forced vital capacity and time to outcomes among patients with idiopathic pulmonary fibrosis. Presented at: American Thoracic Society 2026 International Conference; May 17-20, 2026; Orlando, FL. Abstract 1794.