Estimates of epidemiology, mortality and disease burden associated with progressive fibrosing interstitial lung disease in France (the PROGRESS study)

Abstract

Background: There is a paucity of data on the epidemiology, survival estimates and healthcare resource utilisation and associated costs of patients with progressive fibrosing interstitial lung disease (PF-ILD) in France. An algorithm for extracting claims data was developed to indirectly identify and describe patients with PF-ILD in the French national administrative healthcare database.

Methods: The French healthcare database, the Système National des Données de Santé (SNDS), includes data related to ambulatory care, hospitalisations and death for 98.8% of the population. In this study, algorithms based on age, diagnosis and healthcare consumption were created to identify adult patients with PF-ILD other than idiopathic pulmonary fibrosis between 2010 and 2017. Incidence, prevalence, survival estimates, clinical features and healthcare resource usage and costs were described among patients with PF-ILD.

Results: We identified a total of 14,413 patients with PF-ILD. Almost half of them (48.1%) were female and the mean (± standard deviation) age was 68.4 (± 15.0) years. Between 2010 and 2017, the estimated incidence of PF-ILD ranged from 4.0 to 4.7/100,000 person-years and the estimated prevalence from 6.6 to 19.4/100,000 persons. The main diagnostic categories represented were exposure-related ILD other than hypersensitivity pneumonitis (n = 3486; 24.2%), idiopathic interstitial pneumonia (n = 3113; 21.6%) and rheumatoid arthritis-associated ILD (n = 2521; 17.5%). Median overall survival using Kaplan-Meier estimation was 3.7 years from the start of progression. During the study, 95.2% of patients had ≥ 1 hospitalisation for respiratory care and 34.3% were hospitalised in an intensive care unit. The median (interquartile range) total specific cost per patient during the follow-up period was €25,613 (10,622-54,287) and the median annual cost per patient was €18,362 (6856-52,026), of which €11,784 (3003-42,097) was related to hospitalisations. Limitations included the retrospective design and identification of cases through an algorithm in the absence of chest high-resolution computed tomography scans and pulmonary function tests.

Conclusions: This large, real-world, longitudinal study provides important insights into the characteristics, epidemiology and healthcare resource utilisation and costs associated with PF-ILD in France using a comprehensive and exhaustive database, and provides vital evidence that PF-ILD represents a high burden on both patients and healthcare services. Trial registration ClinicalTrials.gov, NCT03858842. ISRCTN, ISRCTN12345678. Registered 3 January 2019-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03858842.

Keywords: Algorithms; Epidemiology; Healthcare resource utilisation; Interstitial lung disease; Progressive fibrosis.

Fig. 1

Algorithms for the selection of cases of fibrosing ILD with progressive phenotype from the SNDS. a Overview of algorithms and case selection, b algorithm 1 for extraction of patients with fibrosing ILD, c algorithm 2 for extraction of patients with IPF from the fibrosing ILD group, and d algorithm 3 for extraction of patients with fibrosing ILD with a progressive phenotype from the fibrosing ILD group. ¹For full list of ICD-10 codes and definitions see Additional file 1: Table S1. ²For full list of ICD-10 and ATC codes and definitions see Additional file 1: Table S2. ³For full list of CCAM, ATC, GHM, LLP and ICD-10 codes and definitions see Additional file 1: Table S3. ATC anatomical therapeutic chemical classification, CCAM classification commune des actes médicaux [medical classification for clinical procedures], CT computed tomography, GHM groupes homogènes de maladies [Homogeneous Group of Patients], HRCT high-resolution computed tomography, ICD-X International Classification of Diseases code, ILD interstitial lung disease, IPF idiopathic pulmonary fibrosis, LPP liste des produits et prestations [list of products and services], SNDS Système National des Données de Santé [French national administrative healthcare database], TNF tumour necrosis factor.

Fig. 2

Patient flow chart. ID identification, ILD interstitial lung disease, IPF idiopathic pulmonary fibrosis

Fig. 3

Overall survival for PF-ILD. a Overall survival among all patients, and by b sex, c age, and d diagnosis subgroup. Overall survival was defined as the time in years from the date of progression to the date of death due to any cause. Shading indicates 95% Hall–Wellner band. ILD interstitial lung disease, MCTD mixed connective tissue disease, PF-ILD progressive fibrosing interstitial lung disease, RA rheumatoid arthritis, SSc systemic sclerosis

Fig. 3

Overall survival for PF-ILD. a Overall survival among all patients, and by b sex, c age, and d diagnosis subgroup. Overall survival was defined as the time in years from the date of progression to the date of death due to any cause. Shading indicates 95% Hall–Wellner band. ILD interstitial lung disease, MCTD mixed connective tissue disease, PF-ILD progressive fibrosing interstitial lung disease, RA rheumatoid arthritis, SSc systemic sclerosis