The validity of static lung compliance in asbestos-induced diseases

Our plain-English summary of The validity of static lung compliance in asbestos-induced diseases, by J. Schneider, R. Arhelger, W. Raab, et al (Lung, 2012).

The study

• Authors: J. Schneider, R. Arhelger, W. Raab, K.G. Hering
• Journal: Lung
• Published: 2012;190(4):441-9
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Pulmonary compliance can be viewed as an indicator of distensibility of the lungs, not only in asbestos-induced pulmonary disorders but also in visceral pleural fibrosis extending into the lung parenchyma. In this study we evaluated static compliance measurements in asbestos-derived diseases, especially in patients with parietal pleura plaques. Lung function analyses, especially static lung compliance, were correlated with high-resolution computer tomography examinations.

Methods: Sixty-three patients with parietal pleural plaques, 10 with visceral pleural fibrosis, 39 with parenchymal pulmonary asbestosis together with parietal pleural plaques, and 42 with parenchymal pulmonary asbestosis together with visceral pleural fibrosis were enrolled in the study.

Results: In comparison with patients having only parietal pleural plaques, those having asbestosis and visceral pleural fibrosis showed significant decreases in static lung compliance, diffusing capacity, and vital capacity. Visceral pleural thickening was also associated with significantly reduced FEV(1), MEF(50), and FEV(1)/FVC ratios. Multiple regression analyses indicated that the existence of visceral pleural fibrosis (p = 0.017) is the most important factor accounting for a decrease in static compliance. Reference values of static lung compliance differ notably. In comparison with mean reference values, the sensitivity of detecting reduced lung compliance was calculated to be between 9.7 and 45.5 %. Other respiratory function variables failed to show any significant differences.

Conclusion: Our data indicate that the measurement of static compliance is not sufficient for early detection of pulmonary function impairment in patients with parietal pleural plaques.

In plain English

The authors examined whether static lung compliance, a measure of how easily the lungs stretch, helps detect lung function impairment in asbestos-related disease. They studied 154 men with compensated occupational asbestos disease in rehabilitation in Bad Reichenhall, Germany. On high-resolution CT, 63 had parietal pleural plaques only, 10 visceral pleural fibrosis, 39 asbestosis plus parietal pleural plaques, and 42 asbestosis plus visceral pleural fibrosis. Compared with plaques-only men, those with asbestosis plus visceral pleural fibrosis had significantly lower static compliance (mean 2.9 versus 3.9 L/kPa), diffusing capacity and vital capacity. In regression, visceral pleural fibrosis (p = 0.017) was the main factor linked to reduced compliance. Asbestos exposure in fiber-years did not significantly affect lung function. Reduced compliance meant at or below 100% of a published formula's mean reference value, which, the authors noted, half of healthy people fall below. Across five formulas, 15 (9.7%) to 70 (45.5%) of 154 men had reduced compliance. The authors concluded that static compliance measurement is not sufficient for early detection of lung function impairment in patients with parietal pleural plaques.

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 clinical study comparing high-resolution CT findings with lung function tests, including static lung compliance, in groups of patients with different asbestos-related diseases
• Who was studied: 154 consecutive male workers with compensated occupational asbestos disease (German occupational disease No. 4103) in medical rehabilitation at the Berufsgenossenschaftliche Klinik für Berufskrankheiten in Bad Reichenhall, Germany. The groups were 63 with parietal pleural plaques only, 10 with visceral pleural fibrosis, 39 with asbestosis and parietal pleural plaques, and 42 with asbestosis and visceral pleural fibrosis. Nineteen patients with other abnormalities were excluded. Study dates are not given.
• Exposure: Occupational asbestos exposure, with fiber type not specified. Cumulative exposure in fiber-years was estimated by a senior technical inspector from self-reported job histories. Group means ranged from 50.2 to 67.1 fiber-years.
• Main results:
  • Compared with patients having only parietal pleural plaques, those with asbestosis and visceral pleural fibrosis showed significant decreases in static lung compliance, diffusing capacity and vital capacity.
  • Mean static lung compliance was 3.9 L/kPa in the parietal pleural plaques group, 4.2 in the visceral pleural fibrosis group, 3.7 in the asbestosis and parietal pleural plaques group, and 2.9 in the asbestosis and visceral pleural fibrosis group. Only the last group differed significantly from the plaques group (p less than 0.001).
  • The 10 patients with visceral pleural fibrosis had significantly reduced FEV1, MEF50 and FEV1/FVC ratio compared with the parietal pleural plaques group.
  • In multiple regression, visceral pleural fibrosis (p = 0.017) and asbestosis (p = 0.096) were the most important factors accounting for reduced static compliance. The asbestosis p value was above the study's 0.05 significance cutoff.
  • Age was the only significant factor associated with reduced FEV1 (p = 0.008) or inspiratory vital capacity (p = 0.017).
  • Cumulative asbestos exposure in fiber-years did not significantly affect lung function parameters. The data were not shown.
  • Reduced compliance was defined relative to the mean value of published reference formulas, not by an abnormality cutoff. The authors noted that these reference values are medians, so half of normal subjects fall below them.
  • Using the Gillissen reference values, reduced compliance (below 100% of the mean reference value) was found in 15 of 154 patients (9.7%). By group, this was 1 (1.5%) of the 63 with parietal pleural plaques and 11 (26.2%) of the 42 with asbestosis and visceral pleural fibrosis.
  • Using the Quanjer reference values, reduced compliance (below 100% of the mean reference value) was found in 70 of 154 patients (45.5%). By group, this was 23 (36.5%) of the 63 with parietal pleural plaques and 28 (66.6%) of the 42 with asbestosis and visceral pleural fibrosis.
• The authors' conclusion: The authors concluded that measuring static lung compliance is not sufficient for early detection of lung function impairment in patients with parietal pleural plaques.
• Limitations the authors state:
  • Most published reference values for static compliance come from studies done decades ago with few participants, and these reference values differ notably from one another.
  • The reference values are medians, so half of healthy people fall below them.
  • Only men were analyzed, because few women had compensated asbestos-related fibrosis.
  • Because the groups were relatively homogeneous, effects of age, height or other body measurements on compliance could not be observed.

Topics

Medical terms in this study, explained in our Lexicon: Fibrosis, Parenchyma, Parietal Pleura, Pleural Plaques, Asbestosis, Diffusing Capacity (DLCO), Pleural Thickening.

Related studies

• Lung sounds in asbestos induced pulmonary disorders — P. Piirilä, H. Lehtola, et al. (2000)
• Lung function impairment as a guide to exercise limitation in work-related lung disorders — J.E. Cotes, J. Zejda, et al. (1988)
• Asbestos-induced visceral pleural fibrosis reduces pulmonary compliance — E.H. Valkila, M.M. Nieminen, et al. (1995)
• Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS) — J. Szeinuk, C.W. Noonan, et al. (2017)
• Determinants of restrictive lung function in asbestos-induced pleural fibrosis — D.A. Schwartz, J.R. Galvin, et al. (1990)
• Asbestos-induced pleural fibrosis and impaired lung function — D.A. Schwartz, L.J. Fuortes, et al. (1990)

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