A series of algorithms developed to highlight characteristics, epidemiology, and health care information related to progressive fibrosing interstitial lung disease (PF-ILD) suggests a high burden on patients and health care services, according to results from a French real-world study published in Respiratory Research.

A team of investigators conducted a noninterventional, longitudinal, retrospective cohort study (PROGRESS; ClinicalTrials.gov Identifier: NCT03858842) to characterize the incidence and prevalence of PF-ILD in France, to determine PF-ILD in patients at diagnosis, to assess the survival rate, and to describe the health care resources use and linked to direct costs of patients with PF-ILD.

The researchers used administrative claims data from the French national administrative health care database (Système National des Données de Santé [SNDS]) to develop an algorithm that would select patients with PF-ILD other than idiopathic pulmonary fibrosis (IPF).

Continue Reading

Three algorithms were created and included the following criteria: algorithm 1 selected for fibrosing interstitial lung disease (ILD) with either 1 or more claims for qualifying conditions and 1 or more claims for fibrosis, or 2 or more claims for lung fibrosis; algorithm 2 identified cases of IPF; and algorithm 3 selected cases with fibrosing ILD with a progressive phenotype using proxies for PF-ILD.

Eligible patients were aged 20 years and older, met the criteria for PF-ILD, had at least a 2 year history in the SNDS prior to study baseline, and were affiliated with a general reimbursement scheme.

Of the 49,542 people who fit the description for fibrosing ILD, 14,413 patients with PF-ILD met the inclusion criteria for the study. Almost half (48.1%) of the patients were women, the mean patient age was 68.4 years, the median time between diagnosis of fibrosing ILD and meeting the PF-ILD criteria was 0.4 years, and the median duration of follow-up was 1.7 years.

The estimated incidence of PF-ILD, from 2010 to 2017, ranged from 4.0 to 4.7 per 100,000 person-years. The estimated prevalence of PF-ILD ranged from 6.6 to 19.4 per 100,000 person-years.

The most common diagnoses included exposure-related ILD other than hypersensitivity pneumonitis (24.2%), idiopathic interstitial pneumonia (21.6%), rheumatoid arthritis (17.5%), and chronic hypersensitivity pneumonitis (5.1%). The most common comorbidities at baseline were hypertension (63.8%) and gastroesophageal reflux disease (55.4%).

Using Kaplan-Meier estimation, the median overall survival from the start of progression was 3.7 years, and during the analysis, 95.2% and 34.3% of patients had at least 1 hospitalization for respiratory care and were hospitalized in an intensive care unit, respectively.

During the follow-up period, the median total specific cost per patient was €25,613. The median annual cost per patient was €18,362 and €11,784 of this was related to hospitalization.

“Overall, healthcare resource data for investigations and treatments suggest that patients with PF-ILD may not receive sufficient care, and may benefit from being treated in specialised centres,” the study authors noted.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Nasser M, Larrieu S, Boussel L, et al. Estimates of epidemiology, mortality and disease burden associated with progressive fibrosing interstitial lung disease in France (the PROGRESS study). Respir Res. 2021;22(1):162. doi:10.1186/s12931-021-01749-1