Disease progression in patients with usual interstitial pneumonia and probable UIP patterns on computed tomography with various underlying etiologies: a retrospective cohort study

Our plain-English summary of Disease progression in patients with usual interstitial pneumonia and probable UIP patterns on computed tomography with various underlying etiologies: a retrospective cohort study, by S. Yang, J. Wang, D. Sun, et al (Frontiers in Medicine, 2023).

The study

• Authors: S. Yang, J. Wang, D. Sun, Y. Wang, C. Xue, Q. Ye
• Journal: Frontiers in Medicine
• Published: 2023;10:1246767
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Usual interstitial pneumonia (UIP) is a pattern of interstitial pneumonia that is caused by different etiologies. This study aimed to investigate the transplant-free survival (TFS) and the decline in forced vital capacity (FVC) of the patients with UIP and probable UIP patterns on CT caused by various underlying conditions.

Methods: A retrospective cohort study was conducted, enrolling patients with interstitial lung disease exhibiting a CT pattern consistent with UIP or probable UIP. Clinical and prognostic data of patients categorized by the etiology were compared.

Results: A total of 591 patients were included and classified into the following groups: idiopathic pulmonary fibrosis (IPF) (n = 320), connective tissue disease (CTD)-UIP (n = 229), asbestosis-UIP (n = 28), and hypersensitivity pneumonitis (HP)-UIP (n = 14). Advanced age, elevated levels of serum cytokeratin fraction 21-1 and percentage of neutrophils in bronchoalveolar lavage were observed in all groups. IPF patients showed a more rapid decline in FVC (133.9 mL/year) compared to CTD-UIP (24.5 mL/year, p = 0.001) and asbestosis-UIP (61.0 mL/year, p = 0.008) respectively. Sub-analysis of CTD-UIP revealed that patients with rheumatoid arthritis (RA)-UIP (88.1 mL/year) or antineutrophil cytoplasmic antibody-associated vasculitis (AAV)-UIP (72.9 mL/year) experienced a faster deterioration in FVC compared to those with primary Sjögren's syndrome (pSS)-UIP (25.9 mL/year, p < 0.05). Kaplan-Meier curves showed that IPF had the poorest TFS (median 55.9 months), followed by HP-UIP (57.5 months), CTD-UIP (66.7 months), and asbestosis-UIP (TFS not reached). RA-UIP or AAV-UIP did not exhibit any prognostic advantages compared to IPF, while asbestosis-UIP and pSS-UIP showed better survival rates.

Conclusion: Patients with UIP caused by different underlying conditions share certain common features, but the trajectories of disease progression and survival outcomes differ.

Copyright © 2023 Yang, Wang, Sun, Wang, Xue and Ye.

In plain English

This retrospective cohort study at Beijing Chao-Yang Hospital, China, reviewed 591 in-patients newly diagnosed from 2012 to 2021 with interstitial lung disease showing a usual interstitial pneumonia (UIP) or probable UIP pattern on CT scans. Patients were grouped by cause: idiopathic pulmonary fibrosis (IPF, 320), connective tissue disease (229), asbestosis (28) and hypersensitivity pneumonitis (14). All asbestosis patients had a history of exposure to chrysotile asbestos. The median yearly loss of forced vital capacity, a breathing measure, was 133.9 mL in the IPF group and 61.0 mL in the asbestosis-UIP group (p = 0.008). Median survival without lung transplant was 55.9 months for IPF and was not reached for asbestosis-UIP. After adjusting for age, sex, CT pattern, lung function and pulmonary hypertension, the hazard ratio for death or transplant in asbestosis-UIP compared with IPF was 0.154 (95% CI 0.038 to 0.630). The authors concluded that UIP from different causes shares some features but progresses differently, with asbestosis-UIP progressing more slowly than IPF. They cautioned that the asbestosis group was small.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Observational, retrospective, single-center cohort study
• Who was studied: 591 in-patients at Beijing Chao-Yang Hospital, China, newly diagnosed with interstitial lung disease between January 2012 and December 2021 with a UIP or probable UIP pattern on high-resolution CT. They were selected from 9,706 screened patients. Groups were IPF (320), connective tissue disease-UIP (229), asbestosis-UIP (28) and hypersensitivity pneumonitis-UIP (14).
• Exposure: Asbestosis patients were diagnosed using International Labor Organization criteria, and all had a history of chrysotile asbestos exposure. Jobs and doses were not reported. The other groups had non-asbestos causes (unknown cause, connective tissue disease, hypersensitivity pneumonitis).
• Main results:
  • Median yearly decline in forced vital capacity was 133.9 mL/year in the IPF group. This was faster than in the connective tissue disease-UIP group (24.5 mL/year, p = 0.001) and the asbestosis-UIP group (61.0 mL/year, p = 0.008).
  • The IPF group had the poorest transplant-free survival (median 55.9 months).
  • The asbestosis-UIP group had the best transplant-free survival; its median was not reached.
  • In pairwise comparison, transplant-free survival differed significantly between the IPF and asbestosis-UIP groups (log-rank p less than 0.001).
  • Compared with IPF, the asbestosis-UIP group had a hazard ratio for death or lung transplant of 0.154 (95% CI 0.038 to 0.630, p = 0.008). This was after adjustment for age, sex, radiological pattern, lung function and pulmonary hypertension. The unadjusted hazard ratio was 0.320 (95% CI 0.142 to 0.722, p = 0.006).
  • No asbestosis-UIP patient received antifibrotic therapy, compared with 29.7% of IPF patients (p less than 0.001).
  • Median neutrophil proportion in lung-washing (bronchoalveolar lavage) fluid exceeded the normal level of 3% in every group. It was 29.0% in IPF, 30.0% in connective tissue disease-UIP, 23.5% in asbestosis-UIP and 22.0% in hypersensitivity pneumonitis-UIP. Only 6 asbestosis-UIP patients (21.4%) had this test.
  • Within connective tissue disease-UIP, forced vital capacity declined faster in rheumatoid arthritis-UIP (88.1 mL/year) and vasculitis (AAV)-UIP (72.9 mL/year) than in primary Sjögren's syndrome-UIP (25.9 mL/year), p less than 0.05.
• The authors' conclusion: The authors concluded that UIP from various causes shares common features: advanced age, raised serum CYFRA21-1 and more neutrophils in lavage fluid. However, decline in forced vital capacity and transplant-free survival differed by cause. Asbestosis-UIP progressed more slowly and had better survival than IPF, even though the two groups had similar clinical and laboratory features.
• Limitations the authors state:
  • As a retrospective single-center study, it may be prone to selection bias. The asbestosis-UIP and hypersensitivity pneumonitis-UIP groups were relatively small, so some results must be interpreted with caution.
  • Not all patients had a multidisciplinary team assessment at diagnosis, so the cause may have been misjudged in a few patients.
  • Most pathology came from transbronchial biopsies, which prevented a comprehensive analysis of pathological features.
  • Pulmonary hypertension was assessed by echocardiography rather than right heart catheterization, which may have reduced accuracy.
  • Cause of death was not analyzed because most deaths occurred outside the hospital, so the reasons for the survival differences remain unknown.

Topics

Medical terms in this study, explained in our Lexicon: Disease Progression, Interstitial, Cohort Study, Interstitial Lung Disease, Etiology, Idiopathic, Pulmonary Fibrosis, Pneumonitis.

Related studies

• Usual interstitial pneumonia: typical, possible, and "inconsistent" patterns — P.P.T.E.S. Torres, M.F. Rabahi, et al. (2017)
• Usual interstitial pneumonia in asbestos-exposed cohorts - concurrent idiopathic pulmonary fibrosis or atypical asbestosis? — R.L. Attanoos, F.S. Alchami, et al. (2016)
• Patterns of disease progression on 18F-fluorodeoxyglucose positron emission tomography-computed tomography in patients with malignant pleural mesothelioma undergoing multimodality therapy with pleurectomy/decortication — A. Bille, S. Chicklore, et al. (2013)
• Differential diagnosis of usual interstitial pneumonia: when is it truly idiopathic? — W.A. Wuyts, A. Cavazza, et al. (2014)
• Asbestosis and environmental causes of usual interstitial pneumonia — M. Gulati, C.A. Redlich (2015)
• Dyskeratosis congenita showing usual interstitial pneumonia — S. Imokawa, A. Sato, et al. (1994)

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