Epidemiology and mortality of non-idiopathic pulmonary fibrosis (IPF) progressive fibrosing interstitial lung disease (PF-ILD) using the French national health insurance system (SNDS) database in France: the PROGRESS study

Aims: ILDs are a heterogeneous group of disorders with distinct clinical, radiological and prognostic characteristics, which encompass a wide range of conditions. In some patients with fibrosing ILDs, a progressive phenotype similar to that observed in IPF may develop during the course of the disease. The collective estimated prevalence of PF-ILDs is 0.22, 0.59, and 2.0 per 10.000 persons in Belgium, Greece, and France respectively. The PROGRESS study aimed at assessing the epidemiology of non-IPF PF-ILD patients and associated health consumptions and outcomes in a real life nationwide setting in France. Methods: A longitudinal retrospective cohort study was conducted using the French administrative healthcare database (SNDS) between January 2010 and December 2017. Non-IPF PF-ILD patients were identified using an US algorithm based on ICD-10 codes and adapted to French specificities. Results: 17,560 non-IPF PF-ILD patients were identified. In 2017, the prevalence and incidence of non-IPF PF-ILD were respectively 17.9 per 100.000 and 3.0 per 100.000 per year. Sex ratio was close to 1 (51.2% of men) and mean age was 68.5 years (±15.2). Major underlying ILD diagnoses were non-autoimmune-related (50.0%), autoimmune-related (40.0%) and sarcoidosis (10.0%). The median overall survival of non-IPF PF-ILD patients was estimated at 4.1 years. The survival rate was 76.0%, 57.7%, 44.5%, and 33.7% at 1, 3, 5, and 8 years respectively. Conclusion: Based on an algorithm, non-IPF PF-ILD is rare and is associated with a poor prognosis comparable to that of IPF.