Interobserver variations in diagnosing asbestosis according to the ILO classification

Our plain-English summary of Interobserver variations in diagnosing asbestosis according to the ILO classification, by I. Perić, K. Novak, I. Barisić, et al (Arhiv Za Higijenu Rada I Toksikologiju, 2009).

The study

• Authors: I. Perić, K. Novak, I. Barisić, K. Mise, M. Vucković, S. Janković, J. Tocilj
• Journal: Arhiv Za Higijenu Rada I Toksikologiju
• Published: 2009;60(2):191-5
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Inhalation of asbestos fibres leads to asbestosis of the pleura and the lung, with possible progression to lung cancer and malignant pleural or peritoneal mesothelioma. Asbestosis remains difficult to diagnose, especially in its early stages. The most important role in its diagnosis is that of chest radiographs. The aim of this cross-sectional study was to address interobserver variations in interpreting chest radiographs in asbestos workers, which remain to be an issue, despite improvements in the International Labour Office (ILO) classification system. In our ten-year study, we investigated 318 workers occupationally exposed to asbestos, and in 210 workers with diagnosed asbestos-related changes we compared interpretations of chest radiographs according to ILO by two independent radiologists. The apparent degree of interobserver variation in classifying lung fibrosis was 26.66% for the diameter of changes and 42.2% for the profusion of the changes. In cases with diffuse pleural thickening, the interobserver variation using ILO procedures was 34.93%. This investigation raises the issue of standardisation and objectivity of interpretation of asbestosis according to the ILO classification system. This study has revealed a significant disagreement in the estimated degree of pleural and parenchymal asbestos pulmonary disease. This is why we believe high-resolution computed tomography (HRCT) should also be used as a part of international classification.

In plain English

This cross-sectional study from Croatia measured how often two radiologists disagreed when reading chest X-rays of asbestos-exposed workers using the International Labour Office (ILO) classification. The authors examined 318 workers who had worked with asbestos for at least five years at an asbestos cement factory in Vranjic, an asbestos products factory in Ploče and a shipbuilder in Split. They excluded 108 workers, for unknown reasons or because of arterial hypertension, COPD, malignant disease or myocardiopathy, leaving 210. The study used X-rays of workers with diffuse pleural thickening (83) and with small lung opacities (90). Two independent radiologists coded each film. The readers disagreed on the diameter of small lung opacities in 26.66% of cases and on their profusion (how densely they appeared) in 42.22%. For diffuse pleural thickening the disagreement was 34.93%. The authors suggested that fat under the pleura and prominent muscles between the ribs may have been mistaken for pleural disease. They concluded that the ILO system was insufficient and proposed using high-resolution CT. The article did not name the asbestos fiber types.

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: Cross-sectional study comparing chest X-ray readings by two independent radiologists using the ILO classification
• Who was studied: 318 workers in the Dalmatian region of Croatia: 242 men (median age 53) and 76 women (median age 49). 108 were excluded, leaving 210. Chest X-rays were read for workers with verified diffuse pleural thickening (N=83) and small lung opacities (N=90). The authors describe it as a ten-year study but give no calendar dates.
• Exposure: Occupational asbestos exposure of at least five years at an asbestos cement factory (Salonit, Vranjic), a factory of asbestos products (Ploče) and a shipbuilder (BIS, Split). Fiber types and doses were not reported.
• Main results:
  • Of the 318 workers, 108 were excluded: 33 for unknown reasons, 29 for arterial hypertension, 23 for COPD, 12 for malignant disease and 11 for myocardiopathy.
  • The two radiologists disagreed on the diameter of small lung opacities in 26.66% of cases.
  • The two radiologists disagreed on the profusion of small lung opacities in 42.22% of cases.
  • For diffuse pleural thickening in the craniocaudal view, the disagreement between the radiologists was 34.93%.
  • The authors suggested the disagreement on diffuse pleural thickening was possibly caused by subpleural fat and prominent intercostal muscles being misread as pleural disease.
• The authors' conclusion: The authors concluded that the ILO classification system was insufficient because of significant disagreement in establishing pleural and parenchymal asbestos-induced disease. They proposed using high-resolution CT, which they considered superior to the ILO classification for diagnosing asbestosis.

Topics

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

Medical terms in this study, explained in our Lexicon: ILO Classification, Pleura, Lung Cancer, Peritoneal Mesothelioma, Chest X-Ray, Fibrosis, Diffuse Pleural Thickening, High-Resolution CT (HRCT).

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