Prognosis and causes of death of patients with acute exacerbation of fibrosing interstitial lung diseases

Our plain-English summary of Prognosis and causes of death of patients with acute exacerbation of fibrosing interstitial lung diseases, by J. Salonen, M. Purokivi, R. Bloigu, et al (BMJ Open Respiratory Research, 2020).

The study

• Authors: J. Salonen, M. Purokivi, R. Bloigu, R. Kaarteenaho
• Journal: BMJ Open Respiratory Research
• Published: 2020;7(1)
• Cited by: 35 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The aim of this study was to compare the clinical characteristics, causes of death and factors impacting on the prognosis of patients with idiopathic pulmonary fibrosis (IPF) and other fibrosing interstitial lung disease (FILD) with a history of acute exacerbation (AE) of IPF or FILD.

Methods: Retrospective data of hospital treatment periods caused by AE-IPF and AE-FILD were collected from medical records. Clinical features and survival data of IPF and non-IPF cases were evaluated and compared. The underlying and immediate causes of death were gathered from death certificates.

Results: A total of 128 patients fulfilled the criteria for inclusion. IPF (n=79/62%), rheumatoid arthritis-associated interstitial lung disease (RA-ILD; n=17/14%) and asbestosis (n=11/8.6%) were the most common FILD subgroups in the study. The median survival after hospitalisation in AE-IPF was 2.6 months compared with 21 months in other AE-FILDs (p<0.001). The survival difference was not explained by age, gender or pulmonary function test results at the time of hospitalisation. Patients with non-specific interstitial pneumonia and RA-ILD had the most favourable prognosis. ILD was the most common underlying cause of death in both patients with IPF and with other FILD accounting for 87% and 78% of deaths, respectively.

Conclusions: We detected a significantly longer survival in AE of patients with non-IPF compared with that of AE-IPFs. The prognosis of patients was affected by the underlying lung disease since pulmonary fibrosis was the underlying cause of death in the majority of all patients with FILD having experienced an AE.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

In plain English

This retrospective study from northern Finland reviewed records of 128 patients hospitalised at Oulu University Hospital and Oulaskangas Hospital between 2008 and 2017 because of a sudden worsening (acute exacerbation) of a scarring (fibrosing) lung disease. Of these, 79 had idiopathic pulmonary fibrosis (IPF) and 49 had another fibrosing lung disease. Eleven patients (8.6%) had asbestosis. The article did not report quantified asbestos-exposure data. Median survival after hospitalisation was 2.6 months for patients with IPF and 21 months for those with other fibrosing diseases (p<0.001). The difference remained after adjustment for gender, age, smoking and lung function (hazard ratio 2.39, 95% CI 1.41 to 4.05). Across five disease subgroups, patients with IPF or asbestosis seemed to have the shortest survival, and patients with non-specific interstitial pneumonia had the most favourable prognosis. Lung fibrosis was the underlying cause of death in 84% of the patients who died, with no statistically significant difference between the IPF and other groups. The authors concluded that prognosis varied with the underlying lung disease. They listed as limitations the retrospective design, the restriction to two hospitals and the mixed non-IPF group.

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: Retrospective, register-based cohort study using hospital medical records and death certificates
• Who was studied: 128 patients (79 with idiopathic pulmonary fibrosis, 49 with other fibrosing interstitial lung disease) with 142 non-elective hospital treatment periods for acute exacerbation. They were treated at Oulu University Hospital and Oulaskangas Hospital in northern Finland between 1 January 2008 and 31 December 2017.
• Exposure: The article did not report quantified asbestos-exposure data. Asbestosis was one of the lung disease subgroups studied: 11 patients (8.6%), accounting for 13 treatment periods. Other subgroups included rheumatoid arthritis-associated interstitial lung disease and non-specific interstitial pneumonia.
• Main results:
  • Median survival after hospitalisation was 2.6 months in patients with IPF and 21 months in patients with other fibrosing lung diseases (p<0.001).
  • After adjustment for gender, age, smoking, forced vital capacity and diffusion capacity at hospitalisation, the survival difference between IPF and other diseases remained: HR 2.39 (95% CI 1.41 to 4.05), p=0.001.
  • When corticosteroid treatment before hospitalisation was added to the model, the HR was 2.86 (95% CI 1.65 to 4.96), p less than 0.001.
  • Survival depended on the lung disease subtype (p<0.001). Patients with IPF or asbestosis seemed to have the shortest survival, and non-specific interstitial pneumonia had the most favourable prognosis.
  • Among the 107 patients who died, pulmonary fibrosis was the underlying cause of death in 84% and the immediate cause in 45%. By group, it was the underlying cause in 61 of 70 IPF deaths (87%) and 29 of 37 other-disease deaths (78%). The difference was not statistically significant.
  • Sixteen patients (13%) needed invasive mechanical ventilation, and six of them survived the hospital stay.
  • In patients with IPF, corticosteroid treatment before hospitalisation was a risk factor for shorter survival.
• The authors' conclusion: The authors concluded that prognosis after an acute exacerbation varied with the underlying lung disease. They also concluded that pulmonary fibrosis was the underlying cause of death in most patients with fibrosing lung disease who had an exacerbation.
• Limitations the authors state:
  • Retrospective study design
  • Study limited to two hospitals, and the non-IPF group was heterogeneous
  • Some exacerbations may have been missed because of insufficient data, such as lack of high-resolution CT, or faulty diagnosis codes
  • Some deaths from acute exacerbation may not have been recognised, because there is no specific ICD-10 code for exacerbation and imaging is often not done in the terminal phase

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Prognosis, Interstitial Lung Disease, Idiopathic, Pulmonary Fibrosis, Death Certificate, Median Overall Survival, Pulmonary Function Test (PFT), Interstitial.

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• Possible value of antifibrotic drugs in patients with progressive fibrosing non-IPF interstitial lung diseases — S.E. Torrisi, N. Kahn, et al. (2019)
• Differential diagnosis of usual interstitial pneumonia: when is it truly idiopathic? — W.A. Wuyts, A. Cavazza, et al. (2014)
• Validation of the Brazilian Portuguese version of the University of California San Diego Shortness of Breath Questionnaire in patients with interstitial lung disease — H. Silva, L.C. Mantoani, et al. (2021)
• Year in review 2011: acute lung injury, interstitial lung diseases, physiology, sleep and lung cancer — K. Takahashi, N.D. Eves, et al. (2012)

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